JS 數組克隆方法總結(不可更改原數組)

ES5 方法總結

1.slice

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

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'];
arr[0] = 'a';
let arr2 = arr.clone();
console.log(arr,arr2);//['a','bbb','ccc','wwwww','ddd']  ['aaa','bbb','ccc','wwwww','ddd']

3. concat()

Array.prototype.clone=function(){ 
    return [].concat(this); 
    //或者 return this.concat();
　　 //或者 return this.concat([]);

}
let arr = ['aaa','asss']
let arr1 = arr.clone()
arr[0] = 123
console.log(arr,arr1)//[123,'asss']  ['aaa','asss']

ES6 方法總結

1. Object.assign() 淺復制，也可以實現數組的克隆

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