Content provider: Jinniu District Wudi Software Development Studio
To follow:Front-end Development common JS functions (part 1)
- Unique: Unduplicate the array, returning a new array
function unique(arr){
if(! isArrayLink(arr)){// Not an array-like object
return arr
}
let result = []
let objarr = []
let obj = Object.create(null)
arr.forEach(item= > {
if(isStatic(item)){// is the original data except symbol
let key = item + '_' + getRawType(item);
if(! obj[key]){ obj[key] =true
result.push(item)
}
}else{// Reference type and symbol
if(! objarr.includes(item)){ objarr.push(item) result.push(item) } } })return resulte
}
Copy the code- Simple implementation of Set
window.Set = window.Set || (function () {
function Set(arr) {
this.items = arr ? unique(arr) : [];
this.size = this.items.length; // Array size
}
Set.prototype = {
add: function (value) {
// Add the element, skip if the element already exists, and return the Set structure itself.
if (!this.has(value)) {
this.items.push(value);
this.size++;
}
return this;
},
clear: function () {
// Clears all members with no return value.
this.items = []
this.size = 0
},
delete: function (value) {
// Delete a value, return a Boolean value indicating whether the deletion was successful.
return this.items.some((v, i) = > {
if(v === value){
this.items.splice(i,1)
return true
}
return false})},has: function (value) {
// Returns a Boolean value indicating whether the value is a member of Set.
return this.items.some(v= > v === value)
},
values: function () {
return this.items
},
}
return Set; } ());Copy the code- Repeat: Generates a repeated string consisting of n STR that can be modified to fill into an array, etc
function repeat(str, n) {
let res = ' ';
while(n) {
if(n % 2= = =1) {
res += str;
}
if(n > 1) {
str += str;
}
n >>= 1;
}
return res
};
//repeat('123',3) ==> 123123123
Copy the code- DateFormater: format time
function dateFormater(formater, t){
let date = t ? new Date(t) : new Date(),
Y = date.getFullYear() + ' ',
M = date.getMonth() + 1,
D = date.getDate(),
H = date.getHours(),
m = date.getMinutes(),
s = date.getSeconds();
return formater.replace(/YYYY|yyyy/g,Y)
.replace(/YY|yy/g,Y.substr(2.2))
.replace(/MM/g,(M<10?'0':' ') + M)
.replace(/DD/g,(D<10?'0':' ') + D)
.replace(/HH|hh/g,(H<10?'0':' ') + H)
.replace(/mm/g,(m<10?'0':' ') + m)
.replace(/ss/g,(s<10?'0':' ') + s)
}
// dateFormater('YYYY-MM-DD HH:mm', t) ==> 2019-06-26 18:30
// dateFormater('YYYYMMDDHHmm', t) ==> 201906261830
Copy the code- DateStrForma: Converts the specified string from one time format to another. The form From should correspond to the position of STR
function dateStrForma(str, from, to){
//'20190626' 'YYYYMMDD' 'YYYYMMDD'
str += ' '
let Y = ' '
if(~(Y = from.indexOf('YYYY'))){
Y = str.substr(Y, 4)
to = to.replace(/YYYY|yyyy/g,Y)
}else if(~(Y = from.indexOf('YY'))){
Y = str.substr(Y, 2)
to = to.replace(/YY|yy/g,Y)
}
let k,i
['M'.'D'.'H'.'h'.'m'.'s'].forEach(s= >{
i = from.indexOf(s+s)
k = ~i ? str.substr(i, 2) : ' '
to = to.replace(s+s, k)
})
return to
}
// dateStrForma('20190626', 'YYYYMMDD', 'YYYYMMDD') ==> June 26, 2019
// dateStrForma('121220190626', '----YYYYMMDD', 'YYYYMMDD') ==> June 26, 2019
// dateStrForma(' YYYYMMDD', 'YYYYMMDD') ==> 20190626
// This can also be done using regular
/ / 'on June 26, 2019. The replace ()/(\ d {4}) on (\ d {2})/(\ d {2}),' $1 - $2 - $3) = = > 2019-06-26
Copy the code- GetPropByPath: Get object properties based on string path: ‘obj[0].count’
function getPropByPath(obj, path, strict) {
let tempObj = obj;
path = path.replace(/\[(\w+)\]/g.'$1'); // Convert [0] to.0
path = path.replace(/ ^ \. /.' '); // remove the initial.
let keyArr = path.split('. '); // According to.cut
let i = 0;
for (let len = keyArr.length; i < len - 1; ++i) {
if(! tempObj && ! strict)break;
let key = keyArr[i];
if (key in tempObj) {
tempObj = tempObj[key];
} else {
if (strict) {// Enable strict mode, no corresponding key is found, throw an error
throw new Error('please transfer a valid prop path to form item! ');
}
break; }}return {
o: tempObj, // Raw data
k: keyArr[i], / / key values
v: tempObj ? tempObj[keyArr[i]] : null // The value of the key value
};
};
Copy the code- GetUrlParam: Gets the Url argument and returns an object
function GetUrlParam(){
let url = document.location.toString();
let arrObj = url.split("?");
let params = Object.create(null)
if (arrObj.length > 1){
arrObj = arrObj[1].split("&");
arrObj.forEach(item= >{
item = item.split("=");
params[item[0]] = item[1]})}return params;
}
/ /? a=1&b=2&c=3 ==> {a: "1", b: "2", c: "3"}
Copy the code- DownloadFile: base64 Indicates a data export file that can be downloaded
function downloadFile(filename, data) {
let DownloadLink = document.createElement('a');
if (DownloadLink) {
document.body.appendChild(DownloadLink);
DownloadLink.style = 'display: none';
DownloadLink.download = filename;
DownloadLink.href = data;
if (document.createEvent) {
let DownloadEvt = document.createEvent('MouseEvents');
DownloadEvt.initEvent('click'.true.false);
DownloadLink.dispatchEvent(DownloadEvt);
} else if (document.createEventObject) {
DownloadLink.fireEvent('onclick');
} else if (typeof DownloadLink.onclick == 'function') {
DownloadLink.onclick();
}
document.body.removeChild(DownloadLink); }}Copy the code- ToFullScreen: full screen
function toFullScreen() {
let elem = document.body;
elem.webkitRequestFullScreen
? elem.webkitRequestFullScreen()
: elem.mozRequestFullScreen
? elem.mozRequestFullScreen()
: elem.msRequestFullscreen
? elem.msRequestFullscreen()
: elem.requestFullScreen
? elem.requestFullScreen()
: alert("Browser does not support full screen");
}
Copy the code- ExitFullscreen: Exits the full screen
function exitFullscreen() {
let elem = parent.document;
elem.webkitCancelFullScreen
? elem.webkitCancelFullScreen()
: elem.mozCancelFullScreen
? elem.mozCancelFullScreen()
: elem.cancelFullScreen
? elem.cancelFullScreen()
: elem.msExitFullscreen
? elem.msExitFullscreen()
: elem.exitFullscreen
? elem.exitFullscreen()
: alert("Switchover failed. Try Esc to exit.");
}
Copy the code- RequestAnimationFrame: Window animation
window.requestAnimationFrame = window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.msRequestAnimationFrame ||
window.oRequestAnimationFrame ||
function (callback) {
// To get setTimteout as close to 60 frames per second as possible
window.setTimeout(callback, 1000 / 60);
}
window.cancelAnimationFrame = window.cancelAnimationFrame ||
window.webkitCancelAnimationFrame ||
window.mozCancelAnimationFrame ||
window.msCancelAnimationFrame ||
window.oCancelAnimationFrame ||
function (id) {
// To get setTimteout as close to 60 frames per second as possible
window.clearTimeout(id);
}
Copy the code- _isNaN: Checks whether data is a non-numeric value
function _isNaN(v){
return! (typeof v === 'string' || typeof v === 'number') | |isNaN(v)
}
Copy the code- Max: Finds the maximum value of non-nan data in the array
function max(arr){
arr = arr.filter(item= >! _isNaN(item))return arr.length ? Math.max.apply(null, arr) : undefined
}
//max([1, 2, '11', null, 'fdf', []]) ==> 11
Copy the code- Min: Finds the minimum value in the array that is not a NaN
function min(arr){
arr = arr.filter(item= >! _isNaN(item))return arr.length ? Math.min.apply(null, arr) : undefined
}
//min([1, 2, '11', null, 'fdf', []]) ==> 1
Copy the code- Random: Returns a lower-upper direct random number. (Lower, upper must be non-nan data regardless of positive, negative or size)
function random(lower, upper) {
lower = +lower || 0
upper = +upper || 0
return Math.random() * (upper - lower) + lower;
}
/ / the random (0, 0.5) = = > 0.3567039135734613
/ / the random (2, 1) = = = > 1.6718418553475423
/ / the random (2, 1) = = > 1.4474325452361945
Copy the code- Keys: Returns an array of the self-enumerable properties of a given Object
Object.keys = Object.keys || function keys(object) {
if (object === null || object === undefined) {
throw new TypeError('Cannot convert undefined or null to object');
}
let result = [];
if (isArrayLike(object) || isPlainObject(object)) {
for (let key in object) {
object.hasOwnProperty(key) && (result.push(key))
}
}
return result;
}
Copy the code- Object.values: Returns an array of all enumerable property values for a given Object itself
Object.values = Object.values || function values(object) {
if (object === null || object === undefined) {
throw new TypeError('Cannot convert undefined or null to object');
}
let result = [];
if (isArrayLike(object) || isPlainObject(object)) {
for (let key in object) {
object.hasOwnProperty(key) && (result.push(object[key]))
}
}
return result;
}
Copy the code- Arr.fill: Fills the array with values, starting at start and ending at end (but not end), returning the original array
Array.prototype.fill = Array.prototype.fill || function fill(value, start, end) {
let ctx = this
let length = ctx.length;
start = parseInt(start)
if(isNaN(start)){
start = 0
}else if (start < 0) {
start = -start > length ? 0 : (length + start);
}
end = parseInt(end)
if(isNaN(end) || end > length){
end = length
}else if (end < 0) {
end += length;
}
while (start < end) {
ctx[start++] = value;
}
return ctx;
}
//Array(3).fill(2) ===> [2, 2, 2]
Copy the code- Arr.includes: Determines whether an array contains a specified value, returns true if so, false otherwise, and specifies the location to start the query
Array.prototype.includes = Array.prototype.includes || function includes(value, start) {
let ctx = this;
let length = ctx.length;
start = parseInt(start)
if(isNaN(start)) {
start = 0
} else if (start < 0) {
start = -start > length ? 0 : (length + start);
}
let index = ctx.indexOf(value);
return index >= start;
}
Copy the code- Returns the value of the first element in the array that passes the test (judged in function fn)
Array.prototype.find = Array.prototype.find || function find(fn, ctx) {
ctx = ctx || this;
let result;
ctx.some((value, index, arr), thisValue) => {
return fn(value, index, arr) ? (result = value, true) : false
})
return result
}
Copy the code- Arr.findindex: Returns the index of the first element in the array that passes the test (judged in function fn)
Array.prototype.findIndex = Array.prototype.findIndex || function findIndex(fn, ctx){
ctx = ctx || this
let result;
ctx.some((value, index, arr), thisValue) => {
return fn(value, index, arr) ? (result = index, true) : false
})
return result
}
Copy the code- Performance. Timing: Performance. Timing is used to analyze performance
window.onload = function() {
setTimeout(function() {
let t = performance.timing;
console.log('DNS query time: ' + (t.domainLookupEnd - t.domainLookupStart).toFixed(0))
console.log('TCP connection Time: ' + (t.connectEnd - t.connectStart).toFixed(0))
console.log('Request Request time:' + (t.responseEnd - t.responseStart).toFixed(0))
console.log(Dom tree parsing time: + (t.domComplete - t.domInteractive).toFixed(0))
console.log('White screen Time:' + (t.responseStart - t.navigationStart).toFixed(0))
console.log('DomReady time:' + (t.domContentLoadedEventEnd - t.navigationStart).toFixed(0))
console.log('onload time: ' + (t.loadEventEnd - t.navigationStart).toFixed(0))
if (t = performance.memory) {
console.log('JS memory usage ratio:' + (t.usedJSHeapSize / t.totalJSHeapSize * 100).toFixed(2) + The '%')}}}Copy the code- Disallow certain keyboard events
document.addEventListener('keydown'.function(event) {
return! (112 == event.keyCode || / / F1 is prohibited
123 == event.keyCode || / / F12 is prohibited
event.ctrlKey && 82 == event.keyCode || / / CTRL + R is prohibited
event.ctrlKey && 18 == event.keyCode || / / CTRL + N is prohibited
event.shiftKey && 121 == event.keyCode || / / shift + F10 is prohibited
event.altKey && 115 == event.keyCode || / / Alt + F4 is prohibited
"A" == event.srcElement.tagName && event.shiftKey // Disable shift+ clicking on the A TAB) | | (event. ReturnValue =false)});Copy the code- Right-click, select, and copy are prohibited
['contextmenu'.'selectstart'.'copy'].forEach(function(ev) {
document.addEventListener(ev, function(event) {
return event.returnValue = false; })});Copy the codeNext: front-end development common JS function functions (next)