Find the longest character in the array

// Create an array
var stringArr = ['hi'.'i'.'am'.'hahaha'.'hehe']
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Method 1: Go through the number group

 // Record the longest character length and index object, initialization length and index is 0
 var longest = {  
     len: 0.in: 0
    };
stringArr.forEach((item, index) = > {
    if (item.length > longest.len) {
      longest.len = item.length
      longest.in = index
    }
})
console.log('len:', longest.len)
console.log('str:', stringArr[longest.in])

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Method 2: Array sort () method

stringArr.sort((s1, s2) = > {
      return s1.length - s2.length;
})
let longeststr = stringArr.pop();
console.log('str:', longeststr) 
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Method 3: Array reduce() method

var strr = stringArr.reduce((pre, cur) = > {
    return cur.length > pre.length ? cur : pre
})
console.log(strr, strr.length)
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Array to heavy

Method 1: loop through

const unique = []
function uniqueFunc(arr) {
    for (const i = 0; i<arr.length; i++) {if(unique.indexOf(arr[i] === - 1) { // If the current loop element does not exist in the target array, the current element is put into the target array
            unique.push(arr[i])
        }
    }
}
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Method 2: array subscript judgment

function uniqueFunc(arr) {
    const unq = []
    for(const i=0; i<arr.length; i++) {if(arr[i].indexOf(arr[i] === i)) { // If the index of the current loop element in the array is equal to I of the current loop, the element is placed in the target array
            unq.push(arr[i])
        }
    }
}
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Method three: sorting adjacent removal

function uniqueFunc(arr) {
    arr.sort((a,b) = >(a - b)) sort the array firstconst unique = [arr[0]]
    for(const i=0=1; i<arr.length; i++){if(arr[i] ! == arr[i -1]) {
            unique.push(arr[i])
        }
    }
    return unique
}

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Es6 set()

Set () is a new data structure added to ES6 called a collection, similar to an array in that its members are uniqueconst unique = new Set(arr) // This is a similar array that needs to be converted to true
const res = [...unique] // Convert to a true array
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