Licia: the most complete and most useful JavaScript tool library

preface

In business development, we often reuse date formatting, cookie operations, templates, browser judgment, type judgment, and so on. To avoid copy-and-paste between projects, you can wrap these commonly used functions together and distribute NPM packages. In nearly three years of front-end development work, the author encapsulated all the tool libraries I used in daily life into a project Licia. At present, the module has reached 300, which can basically meet the front-end’s daily production needs. If you are interested in this project, please try it out and help to keep improving 🙂

Method of use

Install the NPM package

First install the NPM package locally.

npm i licia --save
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Once installed, you can reference modules directly in your project, just as you would with LoDash.

var uuid = require('licia/uuid');

console.log(uuid()); // -> 0e3b84af-f911-4a55-b78a-cedf6f0bd815
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Second, use the packaging tool

The project comes with the eustia packaging tool, which can automatically generate a project-specific tool library through configuration files or command line scanning of source code.

npm i eustia -g
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If you want to use the trim method in an HTML file, use it directly in your code:

<html>
<head>
    <meta charset="utf-8"/>
    <title>Eustia</title>
    <script src="util.js"></script>
</head>
<body>
    <script>
    var projectName = _.trim(' Eustia ');
    // Some code...
    </script>
</body>
</html>
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Then ran the command:

eustia build
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The tool scans your HTML code and generates an util.js file (the default filename), and you’re done!

PS: the mobile phone debugging tool eruda source code util.js is generated using this tool 🙂

Third, use online tools to generate util library

You can directly access eustia. Liriliri. IO/builder. HTM… Enter the required utility functions (separated by Spaces) in the input box, then click download util. Js file and put it into the project.

For example, if you need to use time formatting in an applet, type dateFormat directly and put the generated util. Js into the applet source code, and then reference it in the code:

import { dateFormat } from './util.js';

dateFormat(1525764204163.'yyyy-mm-dd HH:MM:ss'); / / - > '2018-05-08 15:23:24'
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Summary of Supporting modules

$

jQuery like style dom manipulator.

Available methods

offset, hide, show, first, last, get, eq, on, off, html, text, val, css, attr, data, rmAttr, remove, addClass, rmClass, toggleClass, hasClass, append, prepend, before, after

var $btn = $('#btn');
$btn.html('eustia');
$btn.addClass('btn');
$btn.show();
$btn.on('click'.function ()
{
    // Do something...
});
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$attr

Element attribute manipulation.

Get the value of an attribute for the first element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Attribute name
return	string	Attribute value of first element

Set one or more attributes for the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Attribute name
value	string	Attribute value

Name	Type	Desc
element	string array element	Elements to manipulate
attributes	object	Object of attribute-value pairs to set

remove

Remove an attribute from each element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Attribute name

$attr('#test'.'attr1'.'test');
$attr('#test'.'attr1'); // -> test
$attr.remove('#test'.'attr1');
$attr('#test', {
    'attr1': 'test'.'attr2': 'test'
});
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$class

Element class manipulations.

add

Add the specified class(es) to each element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
names	string array	Classes to add

has

Determine whether any of the matched elements are assigned the given class.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Class name
return	boolean	True if elements has given class name

toggle

Add or remove one or more classes from each element in the set of matched elements, depending on either the class’s presence or the value of the state argument.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Class name to toggle

remove

Remove a single class, multiple classes, or all classes from each element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
names	string	Class names to remove

$class.add('#test', 'class1');
$class.add('#test', ['class1', 'class2']);
$class.has('#test', 'class1'); // -> true
$class.remove('#test', 'class1');
$class.has('#test', 'class1'); // -> false
$class.toggle('#test', 'class1');
$class.has('#test', 'class1'); // -> true
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$css

Element css manipulation.

Get the computed style properties for the first element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Property name
return	string	Css value of first element

Set one or more CSS properties for the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Property name
value	string	Css value

Name	Type	Desc
element	string array element	Elements to manipulate
properties	object	Object of css-value pairs to set

$css('#test', {
    'color': '#fff'.'background': 'black'
});
$css('#test'.'display'.'block');
$css('#test'.'color'); // -> #fff
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$data

Wrapper of $attr, adds data- prefix to keys.

$data('#test'.'attr1'.'eustia');
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$event

bind events to certain dom elements.

function clickHandler()
{
    // Do something...
}
$event.on('#test'.'click', clickHandler);
$event.off('#test'.'click', clickHandler);
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$insert

Insert html on different position.

before

Insert content before elements.

after

Insert content after elements.

prepend

Insert content to the beginning of elements.

append

Insert content to the end of elements.

Name	Type	Desc
element	string array element	Elements to manipulate
content	string	Html strings

// <div id="test"><div class="mark"></div></div>
$insert.before('#test'.'<div>licia</div>');
// -> <div>licia</div><div id="test"><div class="mark"></div></div>
$insert.after('#test'.'<div>licia</div>');
// -> <div id="test"><div class="mark"></div></div><div>licia</div>
$insert.prepend('#test'.'<div>licia</div>');
// -> <div id="test"><div>licia</div><div class="mark"></div></div>
$insert.append('#test'.'<div>licia</div>');
// -> <div id="test"><div class="mark"></div><div>licia</div></div>
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$offset

Get the position of the element in document.

Name	Type	Desc
element	string array element	Elements to get offset

$offset('#test'); // -> {left: 0, top: 0, width: 0, height: 0}
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$property

Element property html, text, val getter and setter.

html

Get the HTML contents of the first element in the set of matched elements or set the HTML contents of every matched element.

text

Get the combined text contents of each element in the set of matched elements, including their descendants, or set the text contents of the matched elements.

val

Get the current value of the first element in the set of matched elements or set the value of every matched element.

$property.html('#test'.'licia');
$property.html('#test'); // -> licia
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$remove

Remove the set of matched elements from the DOM.

Name	Type	Desc
element	string array element	Elements to delete

$remove('#test');
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$safeEls

Convert value into an array, if it’s a string, do querySelector.

Name	Type	Desc
value	element array string	Value to convert
return	array	Array of elements

$safeEls('.test'); // -> Array of elements with test class
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$show

Show elements.

Name	Type	Desc
element	string array element	Elements to show

$show('#test');
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Blob

Use Blob when available, otherwise BlobBuilder.

constructor

Name	Type	Desc
parts	array	Blob parts
[opts]	object	Options

var blob = new Blob([]);
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Class

Create JavaScript class.

Name	Type	Desc
methods	object	Public methods
[statics]	object	Static methods
return	function	Function used to create instances

var People = Class({
    initialize: function People(name, age)
    {
        this.name = name;
        this.age = age;
    },
    introduce: function ()
    {
        return 'I am ' + this.name + ', ' + this.age + ' years old.'; }});var Student = People.extend({
    initialize: function Student(name, age, school)
    {
        this.callSuper(People, 'initialize'.arguments);

        this.school = school;
    },
    introduce: function ()
    {
        return this.callSuper(People, 'introduce') + '\n I study at ' + this.school + '. '; }}, {is: function (obj)
    {
        return obj instanceofStudent; }});var a = new Student('allen'.17.'Hogwarts');
a.introduce(); // -> 'I am allen, 17 years old. \n I study at Hogwarts.'
Student.is(a); // -> true
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Color

Color converter.

constructor

Name	Type	Desc
color	string object	Color to convert

toRgb

Get color rgb string format.

toHex

Get color hex string format.

toHsl

Get color hsl string format.

parse

[static] Parse color string into object containing value and model.

Name	Type	Desc
color	string	Color string
return	object	Object containing value and model

Color.parse('RGB (170, 287, 204, 0.5)'); // -> {val: [170, 187, 204, 0.5], model: 'RGB '}
var color = new Color('#abc');
color.toRgb(); // -> 'rgb(170, 187, 204)'
color.toHsl(); // -> 'hsl(210, 25%, 73%)'
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Dispatcher

Flux dispatcher.

Related docs.

var dispatcher = new Dispatcher();

dispatcher.register(function (payload)
{
   switch (payload.actionType)
   {
       // Do something}}); dispatcher.dispatch({actionType: 'action'
});
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Emitter

Event emitter class which provides observer pattern.

on

Bind event.

off

Unbind event.

once

Bind event that trigger once.

Name	Type	Desc
event	string	Event name
listener	function	Event listener

emit

Emit event.

Name	Type	Desc
event	string	Event name
. args	*	Arguments passed to listener

mixin

[static] Mixin object class methods.

Name	Type	Desc
obj	object	Object to mixin

var event = new Emitter();
event.on('test'.function () { console.log('test')}); event.emit('test'); // Logs out 'test'.
Emitter.mixin({});
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Enum

Enum type implementation.

constructor

Name	Type	Desc
arr	array	Array of strings

Name	Type	Desc
obj	object	Pairs of key and value

var importance = new Enum([
    'NONE'.'TRIVIAL'.'REGULAR'.'IMPORTANT'.'CRITICAL'
]);

if (val === importance.CRITICAL)
{
    // Do something.
}
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JsonTransformer

Json to json transformer.

constructor

Name	Type	Desc
[data={}]	object	Json object to manipulate

set

Set object value.

Name	Type	Desc
[key]	string	Object key
val	*	Value to set

If key is not given, the whole source object is replaced by val.

get

Get object value.

Name	Type	Desc
[key]	string	Object key
return	*	Specified value or whole object

remove

Name	Type	Desc
key	array string	Object keys to remove

map

Shortcut for array map.

Name	Type	Desc
from	string	From object path
to	string	Target object path
fn	function	Function invoked per iteration

filter

Shortcut for array filter.

compute

Compute value from several object values.

Name	Type	Desc
from	array string	Source values
to	string	Target object path
fn	function	Function to compute target value

var data = new JsonTransformer({
    books: [{
        title: 'Book 1'.price: 5
    }, {
        title: 'Book 2'.price: 10}].author: {
        lastname: 'Su'.firstname: 'RedHood'}}); data.filter('books'.function (book) { return book.price > 5 });
data.compute('author'.function (author) { return author.firstname + author.lastname });
data.set('count', data.get('books').length);
data.get(); // -> {books: [{title: 'Book 2', price: 10}], author: 'RedHoodSu', count: 1}
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LinkedList

Doubly-linked list implementation.

push

Add an value to the end of the list.

Name	Type	Desc
val	*	Value to push
return	number	Current size

pop

Get the last value of the list.

unshift

Add an value to the head of the list.

shift

Get the first value of the list.

forEach

Iterate over the list.

toArr

Convert the list to a JavaScript array.

var linkedList = new LinkedList();
linkedList.push(5);
linkedList.pop(); / / - > 5
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LocalStore

LocalStorage wrapper.

Extend from Store.

constructor

Name	Type	Desc
name	string	LocalStorage item name
data	object	Default data

var store = new LocalStore('licia');
store.set('name'.'licia');
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Logger

Simple logger with level filter.

constructor

Name	Type	Desc
name	string	Logger name
[level=DEBUG]	number	Logger level

setLevel

Name	Type	Desc
level	number string	Logger level

getLevel

Get current level.

trace, debug, info, warn, error

Logging methods.

Log Levels

TRACE, DEBUG, INFO, WARN, ERROR and SILENT.

var logger = new Logger('licia', Logger.level.ERROR);
logger.trace('test');

// Format output.
logger.formatter = function (type, argList)
{
    argList.push(new Date().getTime());

    return argList;
};

logger.on('all'.function (type, argList)
{
    // It's not affected by log level.
});

logger.on('debug'.function (argList)
{
    // Affected by log level.
});
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MutationObserver

Safe MutationObserver, does nothing if MutationObserver is not supported.

var observer = new MutationObserver(function (mutations)
{
    // Do something.
});
observer.observe(document.htmlElement);
observer.disconnect();
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Promise

Lightweight Promise implementation.

Promises spec

function get(url)
{
    return new Promise(function (resolve, reject)
    {
        var req = new XMLHttpRequest();
        req.open('GET', url);
        req.onload = function ()
        {
            req.status == 200 ? resolve(req.reponse) : reject(Error(req.statusText));
        };
        req.onerror = function () { reject(Error('Network Error'))}; req.send(); }); } get('test.json').then(function (result)
{
    // Do something...
});
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Queue

Queue data structure.

clear

Clear the queue.

enqueue

Add an item to the queue.

Name	Type	Desc
item	*	Item to enqueue
return	number	Current size

dequeue

Remove the first item of the queue.

peek

Get the first item without removing it.

forEach

Iterate over the queue.

Name	Type	Desc
iteratee	function	Function invoked iteration
[ctx]	*	Function context

toArr

Convert queue to a JavaScript array.

var queue = new Queue();

console.log(queue.size); / / - > 0
queue.enqueue(2);
queue.enqueue(3);
queue.dequeue(); / / - > 2
console.log(queue.size); / / - > 1
queue.peek(); / / - > 3
console.log(queue.size); / / - > 1
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ReduceStore

Simplified redux like state container.

constructor

Name	Type	Desc
reducer	function	Function returns next state
initialState	*	Initial state

Add a change listener.

Name	Type	Desc
listener	function	Callback to invoke on every dispatch
return	function	Function to unscribe

dispatch

Dispatch an action.

Name	Type	Desc
action	object	Object representing changes
return	object	Same action object

getState

Get the current state.

var store = new ReduceStore(function (state, action)
{
    switch (action.type)
    {
        case 'INCREMENT': return state + 1;
        case 'DECREMENT': return state - 1;
        default: returnstate; }},0);

store.subscribe(function ()
{
    console.log(store.getState());
});

store.dispatch({type: 'INCREMENT'}); / / 1
store.dispatch({type: 'INCREMENT'}); / / 2
store.dispatch({type: 'DECREMENT'}); / / 1
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Select

Simple wrapper of querySelectorAll to make dom selection easier.

constructor

Name	Type	Desc
selector	string	Dom selector string

find

Get desdendants of current matched elements.

Name	Type	Desc
selector	string	Dom selector string

each

Iterate over matched elements.

Name	Type	Desc
fn	function	Function to execute for each element

var $test = new Select('#test');
$test.find('.test').each(function (idx, element)
{
    // Manipulate dom nodes
});
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SessionStore

SessionStorage wrapper.

Extend from Store.

constructor

Name	Type	Desc
name	string	SessionStorage item name
data	object	Default data

var store = new SessionStore('licia');
store.set('name'.'licia');
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Stack

Stack data structure.

clear

Clear the stack.

push

Add an item to the stack.

Name	Type	Desc
item	*	Item to add
return	number	Current size

pop

Get the last item of the stack.

peek

Get the last item without removing it.

forEach

Iterate over the stack.

Name	Type	Desc
iteratee	function	Function invoked iteration
[ctx]	*	Function context

toArr

Convert the stack to a JavaScript stack.

var stack = new Stack();

stack.push(2); / / - > 1
stack.push(3); / / - > 2
stack.pop(); / / - > 3
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State

Simple state machine.

Extend from Emitter.

constructor

Name	Type	Desc
initial	string	Initial state
events	string	Events to change state

is

Check current state.

Name	Type	Desc
value	string	State to check
return	boolean	True if current state equals given value

var state = new State('empty', {
    load: {from: 'empty'.to: 'pause'},
    play: {from: 'pause'.to: 'play'},
    pause: {from: ['play'.'empty'].to: 'pause'},
    unload: {from: ['play'.'pause'].to: 'empty'}}); state.is('empty'); // -> true
state.load();
state.is('pause'); // -> true
state.on('play'.function (src)
{
    console.log(src); // -> 'eustia'
});
state.on('error'.function (err, event)
{
    // Error handler
});
state.play('eustia');
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Store

Memory storage.

Extend from Emitter.

constructor

Name	Type	Desc
data	object	Initial data

set

Set value.

Name	Type	Desc
key	string	Value key
val	*	Value to set

Set values.

Name	Type	Desc
vals	object	Key value pairs

This emit a change event whenever is called.

get

Get value.

Name	Type	Desc
key	string	Value key
return	*	Value of given key

Get values.

Name	Type	Desc
keys	array	Array of keys
return	object	Key value pairs

remove

Remove value.

Name	Type	Desc
key	string array	Key to remove

clear

Clear all data.

each

Iterate over values.

Name	Type	Desc
fn	function	Function invoked per interation

var store = new Store('test');
store.set('user', {name: 'licia'});
store.get('user').name; // -> 'licia'
store.clear();
store.each(function (val, key)
{
    // Do something.
});
store.on('change'.function (key, newVal, oldVal)
{
    // It triggers whenever set is called.
});
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Tween

Tween engine for JavaScript animations.

Extend from Emitter.

constructor

Name	Type	Desc
obj	object	Values to tween

to

Name	Type	Desc
destination	obj	Final properties
duration	number	Tween duration
ease	string function	Easing function

play

Begin playing forward.

pause

Pause the animation.

paused

Get animation paused state.

progress

Update or get animation progress.

Name	Type	Desc
[progress]	number	Number between 0 and 1

var pos = {x: 0.y: 0};

var tween = new Tween(pos);
tween.on('update'.function (target)
{
    console.log(target.x, target.y);
}).on('end'.function (target)
{
    console.log(target.x, target.y); / / - > 100, 100
});
tween.to({x: 100.y: 100}, 1000.'inElastic').play();
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Url

Simple url manipulator.

constructor

Name	Type	Desc
url=location	string	Url string

setQuery

Set query value.

Name	Type	Desc
name	string	Query name
value	string	Query value
return	Url	this

Name	Type	Desc
names	object	query object
return	Url	this

rmQuery

Remove query value.

Name	Type	Desc
name	string array	Query name
return	Url	this

parse

[static] Parse url into an object.

Name	Type	Desc
url	string	Url string
return	object	Url object

stringify

[static] Stringify url object into a string.

Name	Type	Desc
url	object	Url object
return	string	Url string

An url object contains the following properties:

Name	Desc
protocol	The protocol scheme of the URL (e.g. http:)
slashes	A boolean which indicates whether the protocol is followed by two forward slashes (//)
auth	Authentication information portion (e.g. username:password)
hostname	Host name without port number
port	Optional port number
pathname	URL path
query	Parsed object containing query string
hash	The “fragment” portion of the URL including the pound-sign (#)

var url = new Url('http://example.com:8080?eruda=true');
console.log(url.port); / / - > '8080'
url.query.foo = 'bar';
url.rmQuery('eruda');
utl.toString(); // -> 'http://example.com:8080/?foo=bar'
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Validator

Object values validation.

constructor

Name	Type	Desc
options	object	Validation configuration

validate

Validate object.

Name	Type	Desc
obj	object	Object to validate
return	*	Validation result, true means ok

addPlugin

[static] Add plugin.

Name	Type	Desc
name	string	Plugin name
plugin	function	Validation handler

Default Plugins

Required, number, boolean, string and regexp.

Validator.addPlugin('custom'.function (val, key, config)
{
    if (typeof val === 'string' && val.length === 5) return true;

    return key + ' should be a string with length 5';
});
var validator = new Validator({
    'test': {
        required: true.custom: true}}); validator.validate({});// -> 'test is required'
validator.validate({test: 1}); // -> 'test should be a string with length 5';
validator.validate({test: 'licia'}); // -> true
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abbrev

Calculate the set of unique abbreviations for a given set of strings.

Name	Type	Desc
. arr	string	List of names
return	object	Abbreviation map

abbrev('lina'.'luna');
// -> {li: 'lina', lin: 'lina', lina: 'lina', lu: 'luna', lun: 'luna', luna: 'luna'}
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after

Create a function that invokes once it’s called n or more times.

Name	Type	Desc
n	number	Number of calls before invoked
fn	function	Function to restrict
return	function	New restricted function

var fn = after(5.function()
{
    // -> Only invoke after fn is called 5 times.
});
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ajax

Perform an asynchronous HTTP request.

Name	Type	Desc
options	object	Ajax options

Available options:

Name	Type	Desc
url	string	Request url
data	string object	Request data
dataType=json	string	Response type(json, xml)
contentType=application/x-www-form-urlencoded	string	Request header Content-Type
success	function	Success callback
error	function	Error callback
complete	function	Callback after request
timeout	number	Request timeout

get

Shortcut for type = GET;

post

Shortcut for type = POST;

Name	Type	Desc
url	string	Request url
[data]	string object	Request data
success	function	Success callback
dataType	function	Response type

ajax({
    url: 'http://example.com'.data: {test: 'true'},
    error: function () {},
    success: function (data)
    {
        // ...
    },
    dataType: 'json'
});

ajax.get('http://example.com', {}, function (data)
{
    // ...
});
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allKeys

Retrieve all the names of object’s own and inherited properties.

Name	Type	Desc
obj	object	Object to query
return	array	Array of all property names

Members of Object’s prototype won’t be retrieved.

var obj = Object.create({zero: 0});
obj.one = 1;
allKeys(obj) // -> ['zero', 'one']
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arrToMap

Make an object map using array of strings.

Name	Type	Desc
arr	array	Array of strings
val=true	*	Key value
return	object	Object map

var needPx = arrToMap([
    'column-count'.'columns'.'font-weight'.'line-weight'.'opacity'.'z-index'.'zoom'
]);

if (needPx[key]) val += 'px';
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atob

Use Buffer to emulate atob when running in node.

atob('SGVsbG8gV29ybGQ='); // -> 'Hello World'
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average

Get average value of given numbers.

Name	Type	Desc
. num	number	Numbers to calculate
return	number	Average value

average(5.3.1); / / - > 3
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base64

Basic base64 encoding and decoding.

encode

Turn a byte array into a base64 string.

Name	Type	Desc
arr	array	Byte array
return	string	Base64 string

base64.encode([168.174.155.255]); // -> 'qK6b/w=='
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decode

Turn a base64 string into a byte array.

Name	Type	Desc
str	string	Base64 string
return	array	Byte array

base64.decode('qK6b/w=='); // -> [168, 174, 155, 255]
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before

Create a function that invokes less than n times.

Name	Type	Desc
n	number	Number of calls at which fn is no longer invoked
fn	function	Function to restrict
return	function	New restricted function

Subsequent calls to the created function return the result of the last fn invocation.

$(element).on('click', before(5.function() {}));
// -> allow function to be call 4 times at last.
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bind

Create a function bound to a given object.

Name	Type	Desc
fn	function	Function to bind
ctx	*	This binding of given fn
[…rest]	*	Optional arguments
return	function	New bound function

var fn = bind(function (msg)
{
    console.log(this.name + ':' + msg);
}, {name: 'eustia'}, 'I am a utility library.');
fn(); // -> 'eustia: I am a utility library.'
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btoa

Use Buffer to emulate btoa when running in node.

btoa('Hello World'); // -> 'SGVsbG8gV29ybGQ='
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bubbleSort

Bubble sort implementation.

Name	Type	Desc
arr	array	Array to sort
[cmp]	function	Comparator

bubbleSort([2.1]); / / - > [1, 2]
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callbackify

Convert a function that returns a Promise to a function following the error-first callback style.

Name	Type	Desc
fn	function	Function that returns a Promise
return	function	Function following the error-fist callback style

function fn()
{
    return new Promise(function (resolve, reject)
    {
        // ...
    });
}

var cbFn = callbackify(fn);

cbFn(function (err, value)
{
    // ...
});
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camelCase

Convert string to “camelCase”.

Name	Type	Desc
str	string	String to convert
return	string	Camel cased string

camelCase('foo-bar'); // -> fooBar
camelCase('foo bar'); // -> fooBar
camelCase('foo_bar'); // -> fooBar
camelCase('foo.bar'); // -> fooBar
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capitalize

Convert the first character to upper case and the remaining to lower case.

Name	Type	Desc
str	string	String to capitalize
return	string	Capitalized string

capitalize('rED'); // -> Red
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castPath

Cast value into a property path array.

Name	Type	Desc
str	*	Value to inspect
[obj]	object	Object to query
return	array	Property path array

castPath('a.b.c'); // -> ['a', 'b', 'c']
castPath(['a']); // -> ['a']
castPath('a[0].b'); // -> ['a', '0', 'b']
castPath('a.b.c', {'a.b.c': true}); // -> ['a.b.c']
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centerAlign

Center align text in a string.

Name	Type	Desc
str	string array	String to align
[width]	number	Total width of each line
return	string	Center aligned string

centerAlign('test'.8); // -> ' test'
centerAlign('test\nlines'.8); // -> ' test\n lines'
centerAlign(['test'.'lines'].8); // -> ' test\n lines'
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char

Return string representing a character whose Unicode code point is the given integer.

Name	Type	Desc
num	number	Integer to convert
return	string	String representing corresponding char

char(65); // -> 'A'
char(97); // -> 'a'
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chunk

Split array into groups the length of given size.

Name	Type	Desc
arr	array	Array to process
size=1	number	Length of each chunk

chunk([1.2.3.4].2); // -> [[1, 2], [3, 4]]
chunk([1.2.3.4].3); // -> [[1, 2, 3], [4]
chunk([1.2.3.4]); // -> [[1], [2], [3], [4]
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clamp

Clamp number within the inclusive lower and upper bounds.

Name	Type	Desc
n	number	Number to clamp
[lower]	number	Lower bound
upper	number	Upper bound
return	number	Clamped number

clamp(- 10.- 5.5); / / - > - 5
clamp(10.- 5.5); / / - > 5
clamp(2.- 5.5); / / - > 2
clamp(10.5); / / - > 5
clamp(2.5); / / - > 2
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className

Utility for conditionally joining class names.

Name	Type	Desc
. class	string object array	Class names
return	string	Joined class names

className('a'.'b'.'c'); // -> 'a b c'
className('a'.false.'b'.0.1.'c'); // -> 'a b 1 c'
className('a'['b'.'c']); // -> 'a b c'
className('a', {b: false.c: true}); // -> 'a c'
className('a'['b'.'c', {d: true.e: false}]); // -> 'a b c d';
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clone

Create a shallow-copied clone of the provided plain object.

Any nested objects or arrays will be copied by reference, not duplicated.

Name	Type	Desc
val	*	Value to clone
return	*	Cloned value

clone({name: 'eustia'}); // -> {name: 'eustia'}
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cloneDeep

Recursively clone value.

Name	Type	Desc
val	*	Value to clone
return	*	Deep cloned Value

var obj = [{a: 1}, {a: 2}];
var obj2 = cloneDeep(obj);
console.log(obj[0] === obj2[1]); // -> false
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cmpVersion

Compare version strings.

Name	Type	Desc
v1	string	Version to compare
v2	string	Version to compare
return	number	Comparison result

cmpVersion('1.1.8'.'1.0.4'); / / - > 1
cmpVersion('1.0.2'.'1.0.2'); / / - > 0
cmpVersion('2.0'.'2.0.0'); / / - > 0
cmpVersion('3.0.1'.'3.0.0.2'); / / - > 1
cmpVersion('1.1.1'."1.2.3"); / / - > 1
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compact

Return a copy of the array with all falsy values removed.

The values false, null, 0, “”, undefined, and NaN are falsey.

Name	Type	Desc
arr	array	Array to compact
return	array	New array of filtered values

compact([0.1.false.2.' '.3]); // -> [1, 2, 3]
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compose

Compose a list of functions.

Each function consumes the return value of the function that follows.

Name	Type	Desc
. fn	function	Functions to compose
return	function	Composed function

var welcome = compose(function (name)
{
    return 'hi: ' + name;
}, function (name)
{
    return name.toUpperCase() + '! ';
});

welcome('licia'); // -> 'hi: LICIA! '
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compressImg

Compress image using canvas.

Name	Type	Desc
file	File Blob	Image file
opts	object	Options
cb	function	Callback

Available options:

Name	Type	Desc
maxWidth	number	Max width
maxHeight	number	Max height
width	number	Output image width
height	number	Output image height
mineType	string	Mine type
Quality = 0.8	number	Image quality, range from 0 to 1

In order to keep image ratio, height will be ignored when width is set.

And maxWith, maxHeight will be ignored if width or height is set.

compressImg(file, {
    maxWidth: 200
}, function (err, file)
{
    // ...
});
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concat

Concat multiple arrays into a single array.

Name	Type	Desc
. arr	array	Arrays to concat
return	array	Concatenated array

concat([1.2], [3], [4.5]); // -> [1, 2, 3, 4, 5]
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contain

Check if the value is present in the list.

Name	Type	Desc
array	array object	Target list
value	*	Value to check
return	boolean	True if value is present in the list

contain([1.2.3].1); // -> true
contain({a: 1.b: 2}, 1); // -> true
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convertBase

Convert base of a number.

Name	Type	Desc
num	number string	Number to convert
from	number	Base from
to	number	Base to
return	string	Converted number

convertBase('10'.2.10); / / - > '2'
convertBase('ff'.16.2); / / - > '11111111'
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cookie

Simple api for handling browser cookies.

get

Get cookie value.

Name	Type	Desc
key	string	Cookie key
return	string	Corresponding cookie value

set

Set cookie value.

Name	Type	Desc
key	string	Cookie key
val	string	Cookie value
[options]	object	Cookie options
return	exports	Module cookie

remove

Remove cookie value.

Name	Type	Desc
key	string	Cookie key
[options]	object	Cookie options
return	exports	Module cookie

cookie.set('a'.'1', {path: '/'});
cookie.get('a'); / / - > '1'
cookie.remove('a');
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copy

Copy text to clipboard using document.execCommand.

Name	Type	Desc
text	string	Text to copy
[cb]	function	Optional callback

copy('text'.function (err)
{
    // Handle errors.
});
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createAssigner

Used to create extend, extendOwn and defaults.

Name	Type	Desc
keysFn	function	Function to get object keys
defaults	boolean	No override when set to true
return	function	Result function, extend…

createUrl

CreateObjectURL wrapper.

Name	Type	Desc
data	File Blob string array	Url data
[opts]	object	Used when data is not a File or Blob
return	string	Blob url

createUrl('test', {type: 'text/plain'}); // -> Blob url
createUrl(['test'.'test']);
createUrl(new Blob([]));
createUrl(new File(['test'].'test.txt'));
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cssSupports

Check if browser supports a given CSS feature.

Name	Type	Desc
name	string	Css property name
[val]	string	Css property value
return	boolean	True if supports

cssSupports('display'.'flex'); // -> true
cssSupports('display'.'invalid'); // -> false
cssSupports('text-decoration-line'.'underline'); // -> true
cssSupports('grid'); // -> true
cssSupports('invalid'); // -> false
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curry

Function currying.

Name	Type	Desc
fn	function	Function to curry
return	function	New curried function

var add = curry(function (a, b) { return a + b });
var add1 = add(1);
add1(2); / / - > 3
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dateFormat

Simple but extremely useful date format function.

Name	Type	Desc
[date=new Date]	Date	Date object to format
mask	string	Format mask
[utc=false]	boolean	UTC or not
[gmt=false]	boolean	GMT or not

Mask	Description
d	Day of the month as digits; no leading zero for single-digit days
dd	Day of the month as digits; leading zero for single-digit days
ddd	Day of the week as a three-letter abbreviation
dddd	Day of the week as its full name
m	Month as digits; no leading zero for single-digit months
mm	Month as digits; leading zero for single-digit months
mmm	Month as a three-letter abbreviation
mmmm	Month as its full name
yy	Year as last two digits; leading zero for years less than 10
yyyy	Year represented by four digits
h	Hours; no leading zero for single-digit hours (12-hour clock)
hh	Hours; leading zero for single-digit hours (12-hour clock)
H	Hours; no leading zero for single-digit hours (24-hour clock)
HH	Hours; leading zero for single-digit hours (24-hour clock)
M	Minutes; no leading zero for single-digit minutes
MM	Minutes; leading zero for single-digit minutes
s	Seconds; no leading zero for single-digit seconds
ss	Seconds; leading zero for single-digit seconds
l L	Milliseconds. l gives 3 digits. L gives 2 digits
t	Lowercase, single-character time marker string: a or p
tt	Lowercase, two-character time marker string: am or pm
T	Uppercase, single-character time marker string: A or P
TT	Uppercase, two-character time marker string: AM or PM
Z	US timezone abbreviation, e.g. EST or MDT
o	GMT/UTC timezone offset, e.g. -0500 or +0230
S	The date’s ordinal suffix (st, nd, rd, or th)
UTC:	Must be the first four characters of the mask

dateFormat('isoDate'); / / - > 2016-11-19
dateFormat('yyyy-mm-dd HH:MM:ss'); / / - > 2016-11-19 19:00:04
dateFormat(new Date(), 'yyyy-mm-dd'); / / - > 2016-11-19
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debounce

Return a new debounced version of the passed function.

Name	Type	Desc
fn	function	Function to debounce
wait	number	Number of milliseconds to delay
return	function	New debounced function

$(window).resize(debounce(calLayout, 300));
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debug

A tiny JavaScript debugging utility.

Name	Type	Desc
name	string	Namespace
return	function	Function to print decorated log

var d = debug('test');
d('doing lots of uninteresting work');
d.enabled = false;
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decodeUriComponent

Better decodeURIComponent that does not throw if input is invalid.

Name	Type	Desc
str	string	String to decode
return	string	Decoded string

decodeUriComponent('% % 25%'); / / - > '% % %'
decodeUriComponent('%E0%A4%A'); // -> '\xE0\xA4%A'
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defaults

Fill in undefined properties in object with the first value present in the following list of defaults objects.

Name	Type	Desc
obj	object	Destination object
*src	object	Sources objects
return	object	Destination object

defaults({name: 'RedHood'}, {name: 'Unknown'.age: 24}); // -> {name: 'RedHood', age: 24}
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define

Define a module, should be used along with use.

Name	Type	Desc
name	string	Module name
[requires]	array	Dependencies
method	function	Module body

The module won’t be executed until it’s used by use function.

define('A'.function ()
{
    return 'A';
});
define('B'['A'].function (A)
{
    return 'B' + A;
});
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defineProp

Shortcut for Object.defineProperty(defineProperties).

Name	Type	Desc
obj	object	Object to define
prop	string	Property path
descriptor	object	Property descriptor
return	object	Object itself

Name	Type	Desc
obj	object	Object to define
prop	object	Property descriptors
return	object	Object itself

var obj = {b: {c: 3}, d: 4.e: 5};
defineProp(obj, 'a', {
    get: function ()
    {
        return this.e * 2; }});console.log(obj.a); / / - > 10
defineProp(obj, 'b.c', {
    set: (function (val)
    {
        // this is pointed to obj.b
        this.e = val;
    }).bind(obj)
});
obj.b.c = 2;
console.log(obj.a); / / - > 4;

obj = {a: 1.b: 2.c: 3};
defineProp(obj, {
    a: {
        get: function ()
        {
            return this.c; }},b: {
        set: function (val)
        {
            this.c = val / 2; }}});console.log(obj.a); / / - > 3
obj.b = 4;
console.log(obj.a); / / - > 2
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delay

Invoke function after certain milliseconds.

Name	Type	Desc
fn	function	Function to delay
wait	number	Number of milliseconds to delay invocation
[…args]	*	Arguments to invoke fn with

delay(function (text)
{
    console.log(text);
}, 1000.'later');
// -> Logs 'later' after one second
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delegate

Event delegation.

add

Add event delegation.

Name	Type	Desc
el	element	Parent element
type	string	Event type
selector	string	Match selector
cb	function	Event callback

remove

Remove event delegation.

var container = document.getElementById('container');
function clickHandler()
{
    // Do something...
}
delegate.add(container, 'click'.'.children', clickHandler);
delegate.remove(container, 'click'.'.children', clickHandler);
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detectBrowser

Detect browser info using ua.

Name	Type	Desc
[ua=navigator.userAgent]	string	Browser userAgent
return	object	Object containing name and version

Browsers supported: ie, chrome, edge, firefox, opera, safari, ios(mobile safari), android(android browser)

var browser = detectBrowser();
if (browser.name === 'ie' && browser.version < 9)
{
    // Do something about old IE...
}
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detectOs

Detect operating system using ua.

Name	Type	Desc
[ua=navigator.userAgent]	string	Browser userAgent
return	string	Operating system name

Supported os: windows, os x, linux, ios, android, windows phone

if (detectOs() === 'ios')
{
    // Do something about ios...
}
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difference

Create an array of unique array values not included in the other given array.

Name	Type	Desc
arr	array	Array to inspect
[…rest]	array	Values to exclude
return	array	New array of filtered values

difference([3.2.1], [4.2]); / / - > [3, 1)
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dotCase

Convert string to “dotCase”.

Name	Type	Desc
str	string	String to convert
return	string	Dot cased string

dotCase('fooBar'); // -> foo.bar
dotCase('foo bar'); // -> foo.bar
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download

Trigger a file download on client side.

Name	Type	Desc
data	Blob File string array	Data to download
name	string	File name
type=text/plain	string	Data type

download('test'.'test.txt');
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each

Iterate over elements of collection and invokes iteratee for each element.

Name	Type	Desc
obj	object array	Collection to iterate over
iteratee	function	Function invoked per iteration
[ctx]	*	Function context

each({'a': 1.'b': 2}, function (val, key) {});
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easing

Easing functions adapted from http://jqueryui.com/

Name	Type	Desc
percent	number	Number between 0 and 1
return	number	Calculated number

easing.linear(0.5); / / - > 0.5
easing.inElastic(0.5.500); / / - > 0.03125
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endWith

Check if string ends with the given target string.

Name	Type	Desc
str	string	The string to search
suffix	string	String suffix
return	boolean	True if string ends with target

endWith('ab'.'b'); // -> true
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escape

Escapes a string for insertion into HTML, replacing &, <, >, “, `, and ‘ characters.

Name	Type	Desc
str	string	String to escape
return	string	Escaped string

escape('You & Me'); -> // -> 'You &amp; Me'
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escapeJsStr

Escape string to be a valid JavaScript string literal between quotes.

http://www.ecma-international.org/ecma-262/5.1/#sec-7.8.4

Name	Type	Desc
str	string	String to escape
return	string	Escaped string

escapeJsStr('\"\n'); // -> '\\"\\\\n'
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escapeRegExp

Escape special chars to be used as literals in RegExp constructors.

Name	Type	Desc
str	string	String to escape
return	string	Escaped string

escapeRegExp('[licia]'); // -> '\\[licia\\]'
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evalCss

Load css into page.

Name	Type	Desc
css	string	Css code

evalCss('body{background:#08c}');
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evalJs

Execute js in given context.

Name	Type	Desc
js	string	JavaScript code
[ctx=global]	object	Context

evalJs('5 + 2'); / / - > 7
evalJs('this.a', {a: 2}); / / - > 2
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every

Check if predicate return truthy for all elements.

Name	Type	Desc
obj	array object	Collection to iterate over
predicate	function	Function invoked per iteration
ctx	*	Predicate context
return	boolean	True if all elements pass the predicate check

every([2.4].function (val)
{
    return val % 2= = =0;
}); // -> false
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extend

Copy all of the properties in the source objects over to the destination object.

Name	Type	Desc
obj	object	Destination object
. src	object	Sources objects
return	object	Destination object

extend({name: 'RedHood'}, {age: 24}); // -> {name: 'RedHood', age: 24}
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extendDeep

Recursive object extending.

Name	Type	Desc
obj	object	Destination object
. src	object	Sources objects
return	object	Destination object

extendDeep({
    name: 'RedHood'.family: {
        mother: 'Jane'.father: 'Jack'}}, {family: {
        brother: 'Bruce'}});// -> {name: 'RedHood', family: {mother: 'Jane', father: 'Jack', brother: 'Bruce'}}
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extendOwn

Like extend, but only copies own properties over to the destination object.

Name	Type	Desc
obj	object	Destination object
*src	object	Sources objects
return	object	Destination object

extendOwn({name: 'RedHood'}, {age: 24}); // -> {name: 'RedHood', age: 24}
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extractBlockCmts

Extract block comments from source code.

Name	Type	Desc
str	string	String to extract
return	array	Block comments

extractBlockCmts('\/*licia*\/'); // -> ['licia']
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extractUrls

Extract urls from plain text.

Name	Type	Desc
str	string	Text to extract
return	array	Url list

var str = '[Official site: http://eustia.liriliri.io](http://eustia.liriliri.io)';
extractUrl(str); // -> ['http://eustia.liriliri.io']
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fetch

Turn XMLHttpRequest into promise like.

Note: This is not a complete fetch pollyfill.

Name	Type	Desc
url	string	Request url
options	object	Request options
return	promise	Request promise

fetch('test.json', {
    method: 'GET'.timeout: 3000.headers: {},
    body: ' '
}).then(function (res)
{
    return res.json();
}).then(function (data)
{
    console.log(data);
});
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fibonacci

Calculate fibonacci number.

Name	Type	Desc
n	number	Index of fibonacci sequence
return	number	Expected fibonacci number

fibonacci(1); / / - > 1
fibonacci(3); / / - > 2
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fileSize

Turn bytes into human readable file size.

Name	Type	Desc
bytes	number	File bytes
return	string	Readable file size

fileSize(5); / / - > '5'
fileSize(1500); / / - > '1.46 K'
fileSize(1500000); / / - > '1.43 M'
fileSize(1500000000); / / - > '1.4 G'
fileSize(1500000000000); / / - > '1.36 T'
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fill

Fill elements of array with value.

Name	Type	Desc
arr	array	Array to fill
val	*	Value to fill array with
start=0	number	Start position
end=arr.length	number	End position
return	array	Filled array

fill([1.2.3].The '*'); // -> ['*', '*', '*']
fill([1.2.3].The '*'.1.2); // -> [1, '*', 3]
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filter

Iterates over elements of collection, returning an array of all the values that pass a truth test.

Name	Type	Desc
obj	array	Collection to iterate over
predicate	function	Function invoked per iteration
[ctx]	*	Predicate context
return	array	Array of all values that pass predicate

filter([1.2.3.4.5].function (val)
{
    return val % 2= = =0;
}); / / - > [2, 4]
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find

Find the first value that passes a truth test in a collection.

Name	Type	Desc
obj	array object	Collection to iterate over
predicate	function	Function invoked per iteration
[ctx]	*	Predicate context
return	*	First value that passes predicate

find([{
    name: 'john'.age: 24
}, {
    name: 'jane'.age: 23}].function (val)
{
    return val.age === 23;
}); // -> {name: 'jane', age: 23}
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findIdx

Return the first index where the predicate truth test passes.

Name	Type	Desc
arr	array	Array to search
predicate	function	Function invoked per iteration
return	number	Index of matched element

findIdx([{
    name: 'john'.age: 24
}, {
    name: 'jane'.age: 23}].function (val)
{
    return val.age === 23;
}); / / - > 1
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findKey

Return the first key where the predicate truth test passes.

Name	Type	Desc
obj	object	Object to search
predicate	function	Function invoked per iteration
[ctx]	*	Predicate context
return	string	Key of matched element

findKey({a: 1.b: 2}, function (val)
{
    return val === 1;
}); // -> a
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findLastIdx

Return the last index where the predicate truth test passes.

Name	Type	Desc
arr	array	Array to search
predicate	function	Function invoked per iteration
return	number	Last index of matched element

findLastIdx([{
    name: 'john'.age: 24
}, {
    name: 'jane'.age: 23
}, {
    name: 'kitty'.age: 24}].function (val)
{
    return val.age === 24;
}); / / - > 2
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flatten

Recursively flatten an array.

Name	Type	Desc
arr	array	Array to flatten
return	array	New flattened array

flatten(['a'['b'['c']], 'd'['e']]); // -> ['a', 'b', 'c', 'd', 'e']
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fnParams

Get a function parameter’s names.

Name	Type	Desc
fn	function	Function to get parameters
return	array	Names

fnParams(function (a, b) {}); // -> ['a', 'b']
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format

Format string in a printf-like format.

Name	Type	Desc
str	string	String to format
. values	*	Values to replace format specifiers
return	string	Formatted string

Format Specifiers

Specifier	Desc
%s	String
%d, %i	Integer
%f	Floating point value
%o	Object

format('%s_%s'.'foo'.'bar'); // -> 'foo bar'
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fraction

Convert number to fraction.

Name	Type	Desc
num	number	Number to convert
return	string	Corresponding fraction

fraction(1.2); / / - > '6/5'
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freeze

Shortcut for Object.freeze.

Use Object.defineProperties if Object.freeze is not supported.

Name	Type	Desc
obj	object	Object to freeze
return	object	Object passed in

var a = {b: 1};
freeze(a);
a.b = 2;
console.log(a); // -> {b: 1}
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freezeDeep

Recursively use Object.freeze.

Name	Type	Desc
obj	object	Object to freeze
return	object	Object passed in

var a = {b: {c: 1}};
freezeDeep(a);
a.b.c = 2;
console.log(a); // -> {b: {c: 1}}
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gcd

Compute the greatest common divisor using Euclid’s algorithm.

Name	Type	Desc
a	number	Number to calculate
b	number	Number to calculate
return	number	Greatest common divisor

gcd(121.44); / / - > 11
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getUrlParam

Get url param.

Name	Type	Desc
name	string	Param name
url=location	string	Url to get param
return	string	Param value

getUrlParam('test'.'http://example.com/?test=true'); // -> 'true'
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has

Checks if key is a direct property.

Name	Type	Desc
obj	object	Object to query
key	string	Path to check
return	boolean	True if key is a direct property

has({one: 1}, 'one'); // -> true
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hotkey

Capture keyboard input to trigger given events.

on

Name	Type	Desc
key	string	Key string
listener	function	Key listener

off

Unregister keyboard listener.

hotkey.on('k'.function ()
{
    console.log('k is pressed');
});
function keyDown() {}
hotkey.on('shift+a, shift+b', keyDown);
hotkey.off('shift+a', keyDown);
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hslToRgb

Convert hsl to rgb.

Name	Type	Desc
hsl	array	Hsl values
return	array	Rgb values

hslToRgb([165.59.50.0.8]); // -> [52, 203, 165, 0.8]
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identity

Return the first argument given.

Name	Type	Desc
val	*	Any value
return	*	Given value

identity('a'); // -> 'a'
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idxOf

Get the index at which the first occurrence of value.

Name	Type	Desc
arr	array	Array to search
val	*	Value to search for
fromIdx=0	number	Index to search from

idxOf([1.2.1.2].2.2); / / - > 3
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indent

Indent each line in a string.

Name	Type	Desc
str	string	String to indent
[char]	string	Character to prepend
[len]	number	Indent length
return	string	Indented string

indent('foo\nbar'.' '.4); // -> 'foo\n bar'
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inherits

Inherit the prototype methods from one constructor into another.

Name	Type	Desc
Class	function	Child Class
SuperClass	function	Super Class

function People(name)
{
    this._name = name;
}
People.prototype = {
    getName: function ()
    {
        return this._name; }};function Student(name)
{
    this._name = name;
}
inherits(Student, People);
var s = new Student('RedHood');
s.getName(); // -> 'RedHood'
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insertionSort

Insertion sort implementation.

Name	Type	Desc
arr	array	Array to sort
[cmp]	function	Comparator

insertionSort([2.1]); / / - > [1, 2]
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intersect

Compute the list of values that are the intersection of all the arrays.

Name	Type	Desc
. arr	array	Arrays to inspect
return	array	New array of inspecting values

intersect([1.2.3.4], [2.1.10], [2.1]); / / - > [1, 2]
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intersectRange

Intersect two ranges.

Name	Type	Desc
a	object	Range a
b	object	Range b
return	object	Intersection if exist

intersectRange({start: 0.end: 12}, {start: 11.end: 13});
// -> {start: 11, end: 12}
intersectRange({start: 0.end: 5}, {start: 6.end: 7});
// -> undefined
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invert

Create an object composed of the inverted keys and values of object.

Name	Type	Desc
obj	object	Object to invert
return	object	New inverted object

If object contains duplicate values, subsequent values overwrite property assignments of previous values unless multiValue is true.

invert({a: 'b'.c: 'd'.e: 'f'}); // -> {b: 'a', d: 'c', f: 'e'}
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isAbsoluteUrl

Check if an url is absolute.

Name	Type	Desc
url	string	Url to check
return	boolean	True if url is absolute

isAbsoluteUrl('http://www.surunzi.com'); // -> true
isAbsoluteUrl('//www.surunzi.com'); // -> false
isAbsoluteUrl('surunzi.com'); // -> false
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isArgs

Check if value is classified as an arguments object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an arguments object

(function () {
    isArgs(arguments); // -> true}) ();Copy the code

isArr

Check if value is an Array object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an `Array` object

isArr([]); // -> true
isArr({}); // -> false
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isArrBuffer

Check if value is an ArrayBuffer.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an ArrayBuffer

isArrBuffer(new ArrayBuffer(8)); // -> true
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isArrLike

Check if value is array-like.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is array like

Function returns false.

isArrLike('test'); // -> true
isArrLike(document.body.children); // -> true;
isArrLike([1.2.3]); // -> true
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isBlob

Check if value is a Blob.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a Blob

isBlob(new Blob([])); // -> true;
isBlob([]); // -> false
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isBool

Check if value is a boolean primitive.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a boolean

isBool(true); // -> true
isBool(false); // -> true
isBool(1); // -> false
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isBrowser

Check if running in a browser.

console.log(isBrowser); // -> true if running in a browser
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isBuffer

Check if value is a buffer.

Name	Type	Desc
val	*	The value to check
return	boolean	True if value is a buffer

isBuffer(new Buffer(4)); // -> true
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isClose

Check if values are close(almost equal) to each other.

abs(a-b) <= max(relTol * max(abs(a), abs(b)), absTol)

Name	Type	Desc
a	number	Number to compare
b	number	Number to compare
relTol=1e-9	number	Relative tolerance
absTol=0	number	Absolute tolerance
return	boolean	True if values are close

isClose(1.1.0000000001); // -> true
isClose(1.2); // -> false
isClose(1.1.2.0.3); // -> true
isClose(1.1.2.0.1.0.3); // -> true
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isDataUrl

Check if a string is a valid data url.

Name	Type	Desc
str	string	String to check
return	boolean	True if string is a data url

isDataUrl('http://eustia.liriliri.io'); // -> false
isDataUrl('data:text/plain; base64,SGVsbG8sIFdvcmxkIQ%3D%3D'); // -> true
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isDate

Check if value is classified as a Date object.

Name	Type	Desc
val	*	value to check
return	boolean	True if value is a Date object

isDate(new Date()); // -> true
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isEl

Check if value is a DOM element.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a DOM element

isEl(document.body); // -> true
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isEmail

Loosely validate an email address.

Name	Type	Desc
val	string	Value to check
return	boolean	True if value is an email like string

isEmail('[email protected]'); // -> true
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isEmpty

Check if value is an empty object or array.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is empty

isEmpty([]); // -> true
isEmpty({}); // -> true
isEmpty(' '); // -> true
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isEqual

Performs an optimized deep comparison between the two objects, to determine if they should be considered equal.

Name	Type	Desc
val	*	Value to compare
other	*	Other value to compare
return	boolean	True if values are equivalent

isEqual([1.2.3], [1.2.3]); // -> true
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isErr

Check if value is an error.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an error

isErr(new Error()); // -> true
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isEven

Check if number is even.

Name	Type	Desc
num	number	Number to check
return	boolean	True if number is even

isOdd(0); // -> true
isOdd(1); // -> false
isOdd(2); // -> true
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isFile

Check if value is a file.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a file

isFile(new File(['test']."test.txt", {type: "text/plain"})); // -> true
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isFinite

Check if value is a finite primitive number.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a finite number

isFinite(3); // -> true
isFinite(Infinity); // -> false
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isFn

Check if value is a function.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a function

Generator function is also classified as true.

isFn(function() {}); // -> true
isFn(function* () {}); // -> true
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isGeneratorFn

Check if value is a generator function.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a generator function

isGeneratorFn(function * () {}); // -> true;
isGeneratorFn(function () {}); // -> false;
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isInt

Checks if value is classified as a Integer.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is correctly classified

isInt(5); // -> true
isInt(5.1); // -> false
isInt({}); // -> false
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isJson

Check if value is a valid JSON.

It uses JSON.parse() and a try... catch block.

Name	Type	Desc
val	string	JSON string
return	boolean	True if value is a valid JSON

isJson('{"a": 5}'); // -> true
isJson("{'a': 5}"); // -> false
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isLeapYear

Check if a year is a leap year.

Name	Type	Desc
year	number	Year to check
return	boolean	True if year is a leap year

isLeapYear(2000); // -> true
isLeapYear(2002); // -> false
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isMatch

Check if keys and values in src are contained in obj.

Name	Type	Desc
obj	object	Object to inspect
src	object	Object of property values to match
return	boolean	True if object is match

isMatch({a: 1.b: 2}, {a: 1}); // -> true
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isMiniProgram

Check if running in wechat mini program.

console.log(isMiniProgram); // -> true if running in mini program.
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isMobile

Check whether client is using a mobile browser using ua.

Name	Type	Desc
[ua=navigator.userAgent]	string	User agent
return	boolean	True if ua belongs to mobile browsers

isMobile(navigator.userAgent);
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isNaN

Check if value is an NaN.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an NaN

Undefined is not an NaN, different from global isNaN function.

isNaN(0); // -> false
isNaN(NaN); // -> true
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isNative

Check if value is a native function.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a native function

isNative(function () {}); // -> false
isNative(Math.min); // -> true
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isNil

Check if value is null or undefined, the same as value == null.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is null or undefined

isNil(null); // -> true
isNil(void 0); // -> true
isNil(undefined); // -> true
isNil(false); // -> false
isNil(0); // -> false
isNil([]); // -> false
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isNode

Check if running in node.

console.log(isNode); // -> true if running in node
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isNull

Check if value is an Null.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an Null

isNull(null); // -> true
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isNum

Check if value is classified as a Number primitive or object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is correctly classified

isNum(5); // -> true
isNum(5.1); // -> true
isNum({}); // -> false
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isNumeric

Check if value is numeric.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is numeric

isNumeric(1); // -> true
isNumeric('1'); // -> true
isNumeric(Number.MAX_VALUE); // -> true
isNumeric(0144); // -> true
isNumeric(0xFF); // -> true
isNumeric(' '); // -> false
isNumeric('1.1.1'); // -> false
isNumeric(NaN); // -> false
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isObj

Check if value is the language type of Object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an object

Language Spec

isObj({}); // -> true
isObj([]); // -> true
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isOdd

Check if number is odd.

Name	Type	Desc
num	number	Number to check
return	boolean	True if number is odd

isOdd(0); // -> false
isOdd(1); // -> true
isOdd(2); // -> false
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isPlainObj

Check if value is an object created by Object constructor.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a plain object

isPlainObj({}); // -> true
isPlainObj([]); // -> false
isPlainObj(function () {}); // -> false
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isPrimitive

Check if value is string, number, boolean or null.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a primitive

isPrimitive(5); // -> true
isPrimitive('abc'); // -> true
isPrimitive(false); // -> true
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isPromise

Check if value looks like a promise.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value looks like a promise

isPromise(new Promise(function () {})); // -> true
isPromise({}); // -> false
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isRegExp

Check if value is a regular expression.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a regular expression

isRegExp(/a/); // -> true
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isRelative

Check if path appears to be relative.

Name	Type	Desc
path	string	Path to check
return	boolean	True if path appears to be relative

isRelative('README.md'); // -> true
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isRetina

Determine if running on a high DPR device or not.

console.log(isRetina); // -> true if high DPR
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isStr

Check if value is a string primitive.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a string primitive

isStr('licia'); // -> true
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isStream

Check if value is a Node.js stream.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a Node.js stream

var stream = require('stream');

isStream(new stream.Stream()); // -> true
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isTypedArr

Check if value is a typed array.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a typed array

isTypedArr([]); // -> false
isTypedArr(new Unit8Array); // -> true
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isUndef

Check if value is undefined.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is undefined

isUndef(void 0); // -> true
isUndef(null); // -> false
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isUrl

Loosely validate an url.

Name	Type	Desc
val	string	Value to check
return	boolean	True if value is an url like string

isUrl('http://www.example.com?foo=bar&param=test'); // -> true
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isWindows

Check if platform is windows.

console.log(isWindows); // -> true if running on windows
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jsonp

A simple jsonp implementation.

Name	Type	Desc
opts	object	Jsonp Options

Available options:

Name	Type	Desc
url	string	Request url
data	object	Request data
success	function	Success callback
param=callback	string	Callback param
name	string	Callback name
error	function	Error callback
complete	function	Callback after request
timeout	number	Request timeout

jsonp({
    url: 'http://example.com'.data: {test: 'true'},
    success: function (data)
    {
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kebabCase

Convert string to “kebabCase”.

Name	Type	Desc
str	string	String to convert
return	string	Kebab cased string

kebabCase('fooBar'); // -> foo-bar
kebabCase('foo bar'); // -> foo-bar
kebabCase('foo_bar'); // -> foo-bar
kebabCase('foo.bar'); // -> foo-bar
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keyCode

Key codes and key names conversion.

Get key code’s name.

Name	Type	Desc
code	number	Key code
return	string	Corresponding key name

Get key name’s code.

Name	Type	Desc
name	string	Key name
return	number	Corresponding key code

keyCode(13); // -> 'enter'
keyCode('enter'); / / - > 13
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keys

Create an array of the own enumerable property names of object.

Name	Type	Desc
obj	object	Object to query
return	array	Array of property names

keys({a: 1}); // -> ['a']
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last

Get the last element of array.

Name	Type	Desc
arr	array	The array to query
return	*	The last element of array

last([1.2]); / / - > 2
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lazyRequire

Require modules lazily.

var r = lazyRequire(require);

var _ = r('underscore');

// underscore is required only when _ is called.
_().isNumber(5);
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linkify

Hyperlink urls in a string.

Name	Type	Desc
str	string	String to hyperlink
[hyperlink]	function	Function to hyperlink url
return	string	Result string

var str = 'Official site: http://eustia.liriliri.io'
linkify(str); // -> 'Official site: <a href="http://eustia.liriliri.io">http://eustia.liriliri.io</a>'
linkify(str, function (url)
{
    return '<a href="' + url + '" target="_blank">' + url + '</a>';
});
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loadCss

Inject link tag into page with given href value.

Name	Type	Desc
src	string	Style source
cb	function	Onload callback

loadCss('style.css'.function (isLoaded)
{
    // Do something...
});
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loadImg

Load image with given src.

Name	Type	Desc
src	string	Image source
[cb]	function	Onload callback

loadImg('http://eustia.liriliri.io/img.jpg'.function (err, img)
{
    console.log(img.width, img.height);
});
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loadJs

Inject script tag into page with given src value.

Name	Type	Desc
src	string	Script source
cb	function	Onload callback

loadJs('main.js'.function (isLoaded)
{
    // Do something...
});
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longest

Get the longest item in an array.

Name	Type	Desc
arr	array	Array to inspect
return	*	Longest item

longest(['a'.'abcde'.'abc']); // -> 'abcde'
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lowerCase

Convert string to lower case.

Name	Type	Desc
str	string	String to convert
return	string	Lower cased string

lowerCase('TEST'); // -> 'test'
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lpad

Pad string on the left side if it’s shorter than length.

Name	Type	Desc
str	string	String to pad
len	number	Padding length
[chars]	string	String used as padding
return	string	Resulted string

lpad('a'.5); // -> ' a'
lpad('a'.5.The '-'); // -> '----a'
lpad('abc'.3.The '-'); // -> 'abc'
lpad('abc'.5.'ab'); // -> 'ababc'
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ltrim

Remove chars or white-spaces from beginning of string.

Name	Type	Desc
str	string	String to trim
chars	string array	Characters to trim
return	string	Trimmed string

ltrim(' abc '); // -> 'abc '
ltrim('_abc_'.'_'); // -> 'abc_'
ltrim('_abc_'['a'.'_']); // -> 'bc_'
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map

Create an array of values by running each element in collection through iteratee.

Name	Type	Desc
obj	array object	Collection to iterate over
iteratee	function	Function invoked per iteration
[ctx]	*	Function context
return	array	New mapped array

map([4.8].function (n) { return n * n; }); / / - > [16, 64]
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mapObj

Map for objects.

Name	Type	Desc
obj	object	Object to iterate over
iteratee	function	Function invoked per iteration
[ctx]	*	Function context
return	object	New mapped object

mapObj({a: 1.b: 2}, function (val, key) { return val + 1 }); // -> {a: 2, b: 3}
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matcher

Return a predicate function that checks if attrs are contained in an object.

Name	Type	Desc
attrs	object	Object of property values to match
return	function	New predicate function

var objects = [
    {a: 1.b: 2.c: 3 },
    {a: 4.b: 5.c: 6}]; filter(objects, matcher({a: 4.c: 6 })); // -> [{a: 4, b: 5, c: 6 }]
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max

Get maximum value of given numbers.

Name	Type	Desc
. num	number	Numbers to calculate
return	number	Maximum value

max(2.3.1.4.5.2); / / 4.5
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memStorage

Memory-backed implementation of the Web Storage API.

A replacement for environments where localStorage or sessionStorage is not available.

var localStorage = window.localStorage || memStorage;
localStorage.setItem('test'.'licia');
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memoize

Memoize a given function by caching the computed result.

Name	Type	Desc
fn	function	Function to have its output memoized
[hashFn]	function	Function to create cache key
return	function	New memoized function

var fibonacci = memoize(function(n)
{
    return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
});
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methods

Return a sorted list of the names of every method in an object.

Name	Type	Desc
obj	object	Object to check
return	array	Function names in object

methods(console); // -> ['Console', 'assert', 'dir', ...]
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min

Get minimum value of given numbers.

Name	Type	Desc
. num	number	Numbers to calculate
return	number	Minimum value

min(2.3.1.4.5.2); / / 1
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mkdir

Recursively create directories.

Name	Type	Desc
dir	string	Directory to create
[mode=0777]	number	Directory mode
callback	function	Callback

mkdir('/tmp/foo/bar/baz'.function (err)
{
    if (err) console.log(err);
    else console.log('Done');
});
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moment

Tiny moment.js like implementation.

It only supports a subset of moment.js api.

Available methods

format, isValid, isLeapYear, isSame, isBefore, isAfter, year, month, date, hour, minute, second, millisecond, unix, clone, toDate, toArray, toJSON, toISOString, toObject, toString, set, startOf, endOf, add, subtract, diff

Not supported

locale and units like quarter and week.

Note: Format uses dateFormat module, so the mask is not quite the same as moment.js.

moment('20180501').format('yyyy-mm-dd'); / / - > '2018-05-01'
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ms

Convert time string formats to milliseconds.

Turn time string into milliseconds.

Name	Type	Desc
str	string	String format
return	number	Milliseconds

Turn milliseconds into time string.

Name	Type	Desc
num	number	Milliseconds
return	string	String format

ms('1s'); / / - > 1000
ms('1m'); / / - > 60000
ms('1.5 h'); / / - > 5400000
ms('1d'); / / - > 86400000
ms('1y'); / / - > 31557600000
ms('1000'); / / - > 1000
ms(1500); / / - > 's 1.5'
ms(60000); // -> '1m'
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negate

Create a function that negates the result of the predicate function.

Name	Type	Desc
predicate	function	Predicate to negate
return	function	New function

function even(n) { return n % 2= = =0 }
filter([1.2.3.4.5.6], negate(even)); // -> [1, 3, 5]
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nextTick

Next tick for both node and browser.

Name	Type	Desc
cb	function	Function to call

Use process.nextTick if available.

Otherwise setImmediate or setTimeout is used as fallback.

nextTick(function ()
{
    // Do something...
});
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noop

A no-operation function.

noop(); // Does nothing
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normalizePath

Normalize file path slashes.

Name	Type	Desc
path	string	Path to normalize
return	string	Normalized path

normalizePath('\\foo\\bar\\'); // -> '/foo/bar/'
normalizePath('./foo//bar'); // -> './foo/bar'
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now

Gets the number of milliseconds that have elapsed since the Unix epoch.

now(); / / - > 1468826678701
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objToStr

Alias of Object.prototype.toString.

Name	Type	Desc
value	*	Source value
return	string	String representation of given value

objToStr(5); // -> '[object Number]'
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omit

Opposite of pick.

Name	Type	Desc
obj	object	Source object
filter	string array function	Object filter
return	object	Filtered object

omit({a: 1, b: 2}, 'a'); // -> {b: 2}
omit({a: 1, b: 2, c: 3}, ['b', 'c']) // -> {a: 1}
omit({a: 1, b: 2, c: 3, d: 4}, function (val, key)
{
    return val % 2;
}); // -> {b: 2, d: 4}

## once 

Create a function that invokes once.

|Name  |Type    |Desc                   |
|------|--------|-----------------------|
|fn    |function|Function to restrict   |
|return|function|New restricted function|

```javascript
function init() {};
var initOnce = once(init);
initOnce();
initOnce(); // -> init is invoked once
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optimizeCb

Used for function context binding.

orientation

Screen orientation helper.

on

Bind change event.

off

Unbind change event.

get

Get current orientation(landscape or portrait).

orientation.on('change'.function (direction)
{
    console.log(direction); // -> 'portrait'
});
orientation.get(); // -> 'landscape'
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pad

Pad string on the left and right sides if it’s shorter than length.

Name	Type	Desc
str	string	String to pad
len	number	Padding length
chars	string	String used as padding
return	string	Resulted string

pad('a'.5); // -> ' a '
pad('a'.5.The '-'); // -> '--a--'
pad('abc'.3.The '-'); // -> 'abc'
pad('abc'.5.'ab'); // -> 'babca'
pad('ab'.5.'ab'); // -> 'ababa'
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pairs

Convert an object into a list of [key, value] pairs.

Name	Type	Desc
obj	object	Object to convert
return	array	List of [key, value] pairs

pairs({a: 1.b: 2}); // -> [['a', 1], ['b', 2]]
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parallel

Run an array of functions in parallel.

Name	Type	Desc
tasks	array	Array of functions
[cb]	function	Callback once completed

parallel([
    function(cb)
    {
        setTimeout(function () { cb(null.'one')},200);
    },
    function(cb)
    {
        setTimeout(function () { cb(null.'two')},100); }].function (err, results)
{
    // results -> ['one', 'two']
});
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parseArgs

Parse command line argument options, the same as minimist.

Name	Type	Desc
args	array	Argument array
opts	object	Parse options
return	object	Parsed result

options

Name	Type	Desc
names	object	option names
shorthands	object	option shorthands

parseArgs(['eustia'.'--output'.'util.js'.'-w'] and {names: {
        output: 'string'.watch: 'boolean'
    },
    shorthands: {
        output: 'o'.watch: 'w'}});// -> {remain: ['eustia'], output: 'util.js', watch: true}
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partial

Partially apply a function by filling in given arguments.

Name	Type	Desc
fn	function	Function to partially apply arguments to
. partials	*	Arguments to be partially applied
return	function	New partially applied function

var sub5 = partial(function (a, b) { return b - a }, 5);
sub(20); / / - > 15
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pascalCase

Convert string to “pascalCase”.

Name	Type	Desc
str	string	String to convert
return	string	Pascal cased string

pascalCase('fooBar'); // -> FooBar
pascalCase('foo bar'); // -> FooBar
pascalCase('foo_bar'); // -> FooBar
pascalCase('foo.bar'); // -> FooBar
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perfNow

High resolution time up to microsecond precision.

var start = perfNow();

// Do something.

console.log(perfNow() - start);
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pick

Return a filtered copy of an object.

Name	Type	Desc
obj	object	Source object
filter	string array function	Object filter
return	object	Filtered object

pick({a: 1.b: 2}, 'a'); // -> {a: 1}
pick({a: 1.b: 2.c: 3},'b'.'c']) // -> {b: 2, c: 3}
pick({a: 1.b: 2.c: 3.d: 4}, function (val, key)
{
    return val % 2;
}); // -> {a: 1, c: 3}
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pluck

Extract a list of property values.

Name	Type	Desc
obj	object array	Collection to iterate over
key	string array	Property path
return	array	New array of specified property

var stooges = [
    {name: 'moe'.age: 40},
    {name: 'larry'.age: 50},
    {name: 'curly'.age: 60}]; pluck(stooges,'name'); // -> ['moe', 'larry', 'curly']
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precision

Find decimal precision of a given number.

Name	Type	Desc
num	number	Number to check
return	number	Precision

precision(1.234); / / - > 3;
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prefix

Add vendor prefixes to a CSS attribute.

Name	Type	Desc
name	string	Property name
return	string	Prefixed property name

dash

Create a dasherize version.

prefix('text-emphasis'); // -> 'WebkitTextEmphasis'
prefix.dash('text-emphasis'); // -> '-webkit-text-emphasis'
prefix('color'); // -> 'color'
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promisify

Convert callback based functions into Promises.

Name	Type	Desc
fn	function	Callback based function
[multiArgs=false]	boolean	If callback has multiple success value
return	boolean	Result function

If multiArgs is set to true, the resulting promise will always fulfill with an array of the callback’s success values.

var fs = require('fs');

var readFile = promisify(fs.readFile);
readFile('test.js'.'utf-8').then(function (data)
{
    // Do something with file content.
});
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property

Return a function that will itself return the key property of any passed-in object.

Name	Type	Desc
path	string array	Path of the property to get
return	function	New accessor function

var obj = {a: {b: 1}};
property('a')(obj); // -> {b: 1}
property(['a'.'b'])(obj); / / - > 1
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query

Parse and stringify url query strings.

parse

Parse a query string into an object.

Name	Type	Desc
str	string	Query string
return	object	Query object

stringify

Stringify an object into a query string.

Name	Type	Desc
obj	object	Query object
return	string	Query string

query.parse('foo=bar&eruda=true'); // -> {foo: 'bar', eruda: 'true'}
query.stringify({foo: 'bar'.eruda: 'true'}); // -> 'foo=bar&eruda=true'
query.parse('name=eruda&name=eustia'); // -> {name: ['eruda', 'eustia']}
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raf

Shortcut for requestAnimationFrame.

Use setTimeout if native requestAnimationFrame is not supported.

var id = raf(function tick()
{
    // Animation stuff
    raf(tick);
});
raf.cancel(id);
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random

Produces a random number between min and max(inclusive).

Name	Type	Desc
min	number	Minimum possible value
max	number	Maximum possible value
[floating=false]	boolean	Float or not
return	number	Random number

random(1.5); // -> an integer between 0 and 5
random(5); // -> an integer between 0 and 5
random(1.2.5.2.true); /// -> a floating-point number between 1.2 and 5.2
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randomBytes

Random bytes generator.

Use crypto module in node or crypto object in browser if possible.

Name	Type	Desc
size	number	Number of bytes to generate
return	object	Random bytes of given length

randomBytes(5); // -> [55, 49, 153, 30, 122]
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range

Create flexibly-numbered lists of integers.

Name	Type	Desc
[start]	number	Start of the range
end	number	End of the range
step=1	number	Value to increment or decrement by

range(5); // -> [0, 1, 2, 3, 4]
range(0.5.2) // -> [0, 2, 4]
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ready

Invoke callback when dom is ready, similar to jQuery ready.

Name	Type	Desc
fn	function	Callback function

ready(function ()
{
    // It's safe to manipulate dom here.
});
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reduce

Turn a list of values into a single value.

Name	Type	Desc
obj	object array	Collection to iterate over
[iteratee=identity]	function	Function invoked per iteration
[initial]	*	Initial value
[ctx]	*	Function context
return	*	Accumulated value

reduce([1.2.3].function (sum, n) { return sum + n }, 0); / / - > 6
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reduceRight

Right-associative version of reduce.

reduceRight([[1], [2], [3]], function (a, b) { return a.concat(b) }, []); // -> [3, 2, 1]
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reject

Opposite of filter.

Name	Type	Desc
obj	array	Collection to iterate over
predicate	function	Function invoked per iteration
[ctx]	*	Predicate context
return	array	Array of all values that pass predicate

reject([1.2.3.4.5].function (val)
{
    return val % 2= = =0;
}); // -> [1, 3, 5]
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remove

Remove all elements from array that predicate returns truthy for and return an array of the removed elements.

Unlike filter, this method mutates array.

Name	Type	Desc
obj	array	Collection to iterate over
predicate	function	Function invoked per iteration
[ctx]	*	Predicate context
return	array	Array of all values that are removed

var arr = [1.2.3.4.5];
var evens = remove(arr, function (val) { return val % 2= = =0 });
console.log(arr); // -> [1, 3, 5]
console.log(evens); / / - > [2, 4]
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repeat

Repeat string n-times.

Name	Type	Desc
str	string	String to repeat
n	number	Repeat times
return	string	Repeated string

repeat('a'.3); // -> 'aaa'
repeat('ab'.2); // -> 'abab'
repeat(The '*'.0); / / - > '
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restArgs

This accumulates the arguments passed into an array, after a given index.

Name	Type	Desc
function	function	Function that needs rest parameters
startIndex	number	The start index to accumulates
return	function	Generated function with rest parameters

var paramArr = restArgs(function (rest) { return rest });
paramArr(1.2.3.4); // -> [1, 2, 3, 4]
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rgbToHsl

Convert rgb to hsl.

Name	Type	Desc
rgb	array	Rgb values
return	array	Hsl values

rgbToHsl([52.203.165.0.8]); // -> [165, 59, 50, 0.8]
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rmCookie

Loop through all possible path and domain to remove cookie.

Name	Type	Desc
key	string	Cookie key

rmCookie('test');
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rmdir

Recursively remove directories.

Name	Type	Desc
dir	string	Directory to remove
callback	function	Callback

rmdir('/tmp/foo/bar/baz'.function (err)
{
    if (err) console.log (err);
    else console.log('Done');
});
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root

Root object reference, global in nodeJs, window in browser.

rpad

Pad string on the right side if it’s shorter than length.

Name	Type	Desc
str	string	String to pad
len	number	Padding length
chars	string	String used as padding
return	string	Resulted string

rpad('a'.5); // -> 'a '
rpad('a'.5.The '-'); // -> 'a----'
rpad('abc'.3.The '-'); // -> 'abc'
rpad('abc'.5.'ab'); // -> 'abcab'
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rtrim

Remove chars or white-spaces from end of string.

Name	Type	Desc
str	string	String to trim
chars	string array	Characters to trim
return	string	Trimmed string

rtrim(' abc '); // -> ' abc'
rtrim('_abc_'.'_'); // -> '_abc'
rtrim('_abc_'['c'.'_']); // -> '_ab'
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safeCb

Create callback based on input value.

safeDel

Delete object property.

Name	Type	Desc
obj	object	Object to query
path	array string	Path of property to delete
return	*	Deleted value or undefined

var obj = {a: {aa: {aaa: 1}}};
safeDel(obj, 'a.aa.aaa'); / / - > 1
safeDel(obj, ['a'.'aa']); / / - > {}
safeDel(obj, 'a.b'); // -> undefined
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safeGet

Get object property, don’t throw undefined error.

Name	Type	Desc
obj	object	Object to query
path	array string	Path of property to get
return	*	Target value or undefined

var obj = {a: {aa: {aaa: 1}}};
safeGet(obj, 'a.aa.aaa'); / / - > 1
safeGet(obj, ['a'.'aa']); // -> {aaa: 1}
safeGet(obj, 'a.b'); // -> undefined
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safeSet

Set value at path of object.

If a portion of path doesn’t exist, it’s created.

Name	Type	Desc
obj	object	Object to modify
path	array string	Path of property to set
val	*	Value to set

var obj = {};
safeSet(obj, 'a.aa.aaa'.1); // obj = {a: {aa: {aaa: 1}}}
safeSet(obj, ['a'.'aa'].2); // obj = {a: {aa: 2}}
safeSet(obj, 'a.b'.3); // obj = {a: {aa: 2, b: 3}}
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safeStorage

Use storage safely in safari private browsing and older browsers.

Name	Type	Desc
[type=’local’]	string	local or session
return	object	Specified storage

var localStorage = safeStorage('local');
localStorage.setItem('licia'.'util');
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sample

Sample random values from a collection.

Name	Type	Desc
obj	array object	Collection to sample
n	number	Number of values
return	array	Array of sample values

sample([2.3.1].2); / / - > [2, 3]
sample({a: 1.b: 2.c: 3}, 1); / / - > [2]
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scrollTo

Scroll to a target with animation.

Name	Type	Desc
target	element string number	Scroll target
options	object	Scroll options

Options

Name	Type	Default	Desc
tolerance	number	0	Tolerance of target to scroll
duration	number	800	Scroll duration
easing	string function	outQuart	Easing function
callback	function	noop	Function to run once scrolling complete

scrollTo('body', {
    tolerance: 0.duration: 800.easing: 'outQuart'.callback: function () {}});Copy the code

selectionSort

Selection sort implementation.

Name	Type	Desc
arr	array	Array to sort
[cmp]	function	Comparator

selectionSort([2.1]); / / - > [1, 2]
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shuffle

Randomize the order of the elements in a given array.

Name	Type	Desc
arr	array	Array to randomize
return	array	Randomized Array

shuffle([1.2.3]); // -> [3, 1, 2]
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size

Get size of object, length of array like object or the number of keys.

Name	Type	Desc
obj	array object	Collection to inspect
return	number	Collection size

size({a: 1.b: 2}); / / - > 2
size([1.2.3]); / / - > 3
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slice

Create slice of source array or array-like object.

Name	Type	Desc
array	array	Array to slice
[start=0]	number	Start position
[end=array.length]	number	End position, not included

slice([1.2.3.4].1.2); / / - > [2]
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snakeCase

Convert string to “snakeCase”.

Name	Type	Desc
str	string	String to convert
return	string	Snake cased string

snakeCase('fooBar'); // -> foo_bar
snakeCase('foo bar'); // -> foo_bar
snakeCase('foo.bar'); // -> foo_bar
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some

Check if predicate return truthy for any element.

Name	Type	Desc
obj	array object	Collection to iterate over
predicate	function	Function to invoked per iteration
ctx	*	Predicate context
return	boolean	True if any element passes the predicate check

some([2.5].function (val)
{
    return val % 2= = =0;
}); // -> true
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spaceCase

Convert string to “spaceCase”.

Name	Type	Desc
str	string	String to convert
return	string	Space cased string

spaceCase('fooBar'); // -> foo bar
spaceCase('foo.bar'); // -> foo bar
spaceCase('foo.bar'); // -> foo bar
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splitCase

Split different string case to an array.

Name	Type	Desc
str	string	String to split
return	array	Result array

splitCase('foo-bar'); // -> ['foo', 'bar']
splitCase('foo bar'); // -> ['foo', 'bar']
splitCase('foo_bar'); // -> ['foo', 'bar']
splitCase('foo.bar'); // -> ['foo', 'bar']
splitCase('fooBar'); // -> ['foo', 'bar']
splitCase('foo-Bar'); // -> ['foo', 'bar']
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splitPath

Split path into device, dir, name and ext.

Name	Type	Desc
path	string	Path to split
return	object	Object containing dir, name and ext

splitPath('f:/foo/bar.txt'); // -> {dir: 'f:/foo/', name: 'bar.txt', ext: '.txt'}
splitPath('/home/foo/bar.txt'); // -> {dir: '/home/foo/', name: 'bar.txt', ext: '.txt'}
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startWith

Check if string starts with the given target string.

Name	Type	Desc
str	string	String to search
prefix	string	String prefix
return	boolean	True if string starts with prefix

startWith('ab'.'a'); // -> true
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strHash

String hash function using djb2.

Name	Type	Desc
str	string	String to hash
return	number	Hash result

strHash('test'); / / - > 2090770981
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stringify

JSON stringify with support for circular object, function etc.

Undefined is treated as null value.

Name	Type	Desc
obj	object	Object to stringify
spaces	number	Indent spaces
return	string	Stringified object

stringify({a: function () {}}); // -> '{"a":"[Function function () {}]"}'
var obj = {a: 1};
obj.b = obj;
stringify(obj); // -> '{"a":1,"b":"[Circular ~]"}'
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stripAnsi

Strip ansi codes from a string.

Name	Type	Desc
str	string	String to strip
return	string	Resulted string

stripAnsi('\u001b[4mcake\u001b[0m'); // -> 'cake'
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stripCmt

Strip comments from source code.

Name	Type	Desc
str	string	Source code
return	string	Code without comments

stripCmts('// comment \n var a = 5; /* comment2\n * comment3\n *\/'); // -> ' var a = 5; '
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stripColor

Strip ansi color codes from a string.

Name	Type	Desc
str	string	String to strip
return	string	Resulted string

stripColor('\u001b[31mred\u001b[39m'); // -> 'red'
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stripHtmlTag

Strip html tags from a string.

Name	Type	Desc
str	string	String to strip
return	string	Resulted string

stripHtmlTag('<p>Hello</p>'); // -> 'Hello'
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sum

Compute sum of given numbers.

Name	Type	Desc
. num	number	Numbers to calculate
return	number	Sum of numbers

sum(1.2.5); / / - > 8
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template

Compile JavaScript template into function that can be evaluated for rendering.

Name	Type	String
str	string	Template string
return	function	Compiled template function

template('Hello <%= name %>! ') ({name: 'licia'}); // -> 'Hello licia! '
template('<p><%- name %></p>') ({name: '<licia>'}); // -> '< licia> 
'
template('<%if (echo) {%>Hello licia! < %} % > ') ({echo: true}); // -> 'Hello licia! '
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throttle

Return a new throttled version of the passed function.

Name	Type	Desc
fn	function	Function to throttle
wait	number	Number of milliseconds to delay
return	function	New throttled function

$(window).scroll(throttle(updatePos, 100));
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through

Tiny wrapper of stream Transform.

Name	Type	Desc
[opts={}]	Object	Options to initialize stream
transform	function	Transform implementation
[flush]	function	Flush implementation

obj

Shortcut for setting objectMode to true.

ctor

Return a class that extends stream Transform.

fs.createReadStream('in.txt')
  .pipe(through(function (chunk, enc, cb)
  {
      // Do something to chunk
      this.push(chunk);
      cb();
  })).pipe(fs.createWriteStream('out.txt'));
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timeAgo

Format datetime with *** time ago statement.

Name	Type	Desc
date	Date	Date to calculate
[now=new Date]	Date	Current date
return	string	Formatted time ago string

var now = new Date().getTime();
timeAgo(now - 1000 * 6); // -> right now
timeAgo(now + 1000 * 15); // -> in 15 minutes
timeAgo(now - 1000 * 60 * 60 * 5, now); // -> 5 hours ago
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timeTaken

Get execution time of a function.

Name	Type	Desc
fn	function	Function to measure time
return	number	Execution time, ms

timeTaken(function ()
{
    // Do something.
}); // -> Time taken to execute given function.
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toArr

Convert value to an array.

Name	Type	Desc
val	*	Value to convert
return	array	Converted array

toArr({a: 1.b: 2}); // -> [{a: 1, b: 2}]
toArr('abc'); // -> ['abc']
toArr(1); / / - > [1]
toArr(null); / / - > []
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toBool

Convert value to a boolean.

Name	Type	Desc
val	*	Value to convert
return	boolean	Converted boolean

toBool(true); // -> true
toBool(null); // -> false
toBool(1); // -> true
toBool(0); // -> false
toBool('0'); // -> false
toBool('1'); // -> true
toBool('false'); // -> false
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toDate

Convert value to a Date.

Name	Type	Desc
val	*	Value to convert
return	Date	Converted Date

toDate('20180501');
toDate('2018-05-01');
toDate(1525107450849);
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toEl

Convert html string to dom elements.

There should be only one root element.

Name	Type	Desc
str	string	Html string
return	element	Html element

toEl('<div>test</div>');
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toInt

Convert value to an integer.

Name	Type	Desc
val	*	Value to convert
return	number	Converted integer

toInt(1.1); / / - > 1
toInt(undefined); / / - > 0
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toNum

Convert value to a number.

Name	Type	Desc
val	*	Value to process
return	number	Resulted number

toNum('5'); / / - > 5
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toSrc

Convert function to its source code.

Name	Type	Desc
fn	function	Function to convert
return	string	Source code

toSrc(Math.min); // -> 'function min() { [native code] }'
toSrc(function () {}) // -> 'function () { }'
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toStr

Convert value to a string.

Name	Type	Desc
val	*	Value to convert
return	string	Resulted string

toStr(null); / / - > '
toStr(1); / / - > '1'
toStr(false); // -> 'false'
toStr([1.2.3]); / / - > '1, 2, 3'
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topoSort

Topological sorting algorithm.

Name	Type	Desc
edges	array	Dependencies
return	array	Sorted order

topoSort([[1.2], [1.3], [3.2]]); // -> [1, 3, 2]
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trigger

Trigger browser events.

Name	Type	Desc
[el=document]	element	Element to trigger
type	string	Event type
opts	object	Options

trigger(el, 'mouseup');
trigger('keydown', {keyCode: 65});
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trim

Remove chars or white-spaces from beginning end of string.

Name	Type	Desc
str	string	String to trim
chars	string array	Characters to trim
return	string	Trimmed string

trim(' abc '); // -> 'abc'
trim('_abc_'.'_'); // -> 'abc'
trim('_abc_'['a'.'c'.'_']); // -> 'b'
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tryIt

Run function in a try catch.

Name	Type	Desc
fn	function	Function to try catch
[cb]	function	Callback

tryIt(function ()
{
    // Do something that might cause an error.
}, function (err, result)
{
    if (err) console.log(err);
});
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type

Determine the internal JavaScript [[Class]] of an object.

Name	Type	Desc
val	*	Value to get type
return	string	Type of object, lowercased

type(5); // -> 'number'
type({}); // -> 'object'
type(function () {}); // -> 'function'
type([]); // -> 'array'
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ucs2

UCS-2 encoding and decoding.

encode

Create a string using an array of code point values.

Name	Type	Desc
arr	array	Array of code points
return	string	Encoded string

decode

Create an array of code point values using a string.

Name	Type	Desc
str	string	Input string
return	array	Array of code points

ucs2.encode([0x61.0x62.0x63]); // -> 'abc'
ucs2.decode('abc'); // -> [0x61, 0x62, 0x63]
'𝌆'.length; / / - > 2
ucs2.decode('𝌆').length; / / - > 1
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unescape

Convert HTML entities back, the inverse of escape.

Name	Type	Desc
str	string	String to unescape
return	string	unescaped string

unescape('You &amp; Me'); -> // -> 'You & Me'
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union

Create an array of unique values, in order, from all given arrays.

Name	Type	Desc
. arr	array	Arrays to inspect
return	array	New array of combined values

union([2.1], [4.2], [1.2]); // -> [2, 1, 4]
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uniqId

Generate a globally-unique id.

Name	Type	Desc
prefix	string	Id prefix
return	string	Globally-unique id

uniqId('eusita_'); // -> 'eustia_xxx'
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unique

Create duplicate-free version of an array.

Name	Type	Desc
arr	array	Array to inspect
[compare]	function	Function for comparing values
return	array	New duplicate free array

unique([1.2.3.1]); // -> [1, 2, 3]
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unzip

Opposite of zip.

Name	Type	Desc
arr	array	Array of grouped elements to process
return	array	New array of regrouped elements

unzip([['a'.1.true], ['b'.2.false]]); // -> [['a', 'b'], [1, 2], [true, false]]
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upperCase

Convert string to upper case.

Name	Type	Desc
str	string	String to convert
return	string	Uppercased string

upperCase('test'); // -> 'TEST'
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upperFirst

Convert the first character of string to upper case.

Name	Type	Desc
str	string	String to convert
return	string	Converted string

upperFirst('red'); // -> Red
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use

Use modules that is created by define.

Name	Type	Desc
[requires]	array	Dependencies
method	function	Codes to be executed

define('A'.function ()
{
    return 'A';
});
use(['A'].function (A)
{
    console.log(A + 'B'); // -> 'AB'
});
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utf8

UTF-8 encoding and decoding.

encode

Turn any UTF-8 decoded string into UTF-8 encoded string.

Name	Type	Desc
str	string	String to encode
return	string	Encoded string

decode

Name	Type	Desc
str	string	String to decode
[safe=false]	boolean	Suppress error if true
return	string	Decoded string

Turn any UTF-8 encoded string into UTF-8 decoded string.

utf8.encode('\uD800\uDC00'); // -> '\xF0\x90\x80\x80'
utf8.decode('\xF0\x90\x80\x80'); // -> '\uD800\uDC00'
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uuid

RFC4122 version 4 compliant uuid generator.

Check RFC4122 4.4 for reference.

uuid(); // -> '53ce0497-6554-49e9-8d79-347406d2a88b'
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values

Create an array of the own enumerable property values of object.

Name	Type	Desc
obj	object	Object to query
return	array	Array of property values

values({one: 1.two: 2}); / / - > [1, 2]
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viewportScale

Get viewport scale.

viewportScale(); / / - > 3
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waterfall

Run an array of functions in series.

Name	Type	Desc
tasks	array	Array of functions
[cb]	function	Callback once completed

waterfall([
    function (cb)
    {
        cb(null.'one');
    },
    function (arg1, cb)
    {
        // arg1 -> 'one'
        cb(null.'done'); }].function (err, result)
{
    // result -> 'done'
});
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workerize

Move a stand-alone function to a worker thread.

Name	Type	Desc
fn	function	Function to turn
return	function	Workerized Function

workerize(function (a, b)
{
    return a + b;
});
workerize(1.2).then(function (value)
{
    console.log(value); / / - > 3
});
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wrap

Wrap the function inside a wrapper function, passing it as the first argument.

Name	Type	Desc
fn	*	Function to wrap
wrapper	function	Wrapper function
return	function	New function

var p = wrap(escape.function(fn, text)
{
    return '<p>' + fn(text) + '</p>';
});
p('You & Me'); // -> '<p>You &amp; Me</p>'
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zip

Merge together the values of each of the arrays with the values at the corresponding position.

Name	Type	Desc
*arr	array	Arrays to process
return	array	New array of grouped elements

zip(['a'.'b'], [1.2], [true.false]); // -> [['a', 1, true], ['b', 2, false]]
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