JS 數組克隆方法總結

ES5 方法總結

1.slice

let arr = [2,4,434,43]
let arr1= arr.slice()
arr[0] = 'a'
console.log(arr,arr1) // [ 2, 4, 434, 43 ]
console.log(arr1 === arr) // false

2. 遍歷數組

Array.prototype.clone = function(){
    let a=[];
    for(let i=0,l=this.length;i<l;i++) {
        a.push(this[i]);
    }
    return a;
}
let arr = ['aaa','bbb','ccc','wwwww','ddd']
let arr2 = arr.clone()
console.log(arr2)
console.log( arr2 === arr )

3. concat()

Array.prototype.clone=function(){ 
    return [].concat(this); 
    //或者 return this.concat();
}
let arr = ['aaa','asss']
let arr1 = arr.clone()
arr[0] = 123
console.log(arr,arr1)

ES6 方法總結

1. Object.assign() 淺複製，也能夠實現數組的克隆

let arr = ['sdsd',123,123,123]
let arr1 = []
Object.assign(arr1,arr)
arr[1] = 'aaaa'
console.log(arr,arr1) // [ 'sdsd', 'aaaa', 123, 123 ] [ 'sdsd', 123, 123, 123 ]

 2. 擴展運算符

const a1 = [1, 2];
// 寫法一
const a2 = [...a1];
a1[0] = 'aaa'
console.log(a1,a2)