示例JS 數組和對象的深拷貝操作

本文實例講述了JS 數組和對象的深拷貝操作。分享給大家供大家參考，具體如下：

一.數組的深拷貝

let arr = [  undefined,  function(){   console.log(123);   },  true,  null,  {   name:"123",   age:23  } ]; // arr作為拷貝對象

1. Array.from()

Array.from()能將一個類數組轉化成一個真正的數組，因此它返回的是一個新數組。

let arr1 = Array.from(arr); arr[0] = 2; console.log(arr1); // [ undefined, [Function], true, null, { name: '123', age: 23 } ]

2. Object.assign()

let arr1 = Object.assign([], arr) arr[0] = 2; console.log(arr1); // [ undefined, [Function], true, null, { name: '123', age: 23 } ]

此方法也可用作對象的深拷貝

3. Slice()

let arr1 = arr.slice(0); arr[0] = 2; console.log(arr1); // [ undefined, [Function], true, null, { name: '123', age: 23 } ]

4. Concat()

let arr1 = arr.concat(); arr[0] = 2; console.log(arr1); // [ undefined, [Function], true, null, { name: '123', age: 23 } ]

5. 擴展運算符深拷貝

// let [...arr1] = arr; // 這兩種都可以 let arr1 = [...arr]; arr[0] = 2; console.log(arr1); // [ undefined, [Function], true, null, { name: '123', age: 23 } ]

此方法也可用作對象的深拷貝

二.對象的深拷貝

let obj = {  name: "a",  age: 20,  sex: false,  user: {   a: 20,   n: "b"  },  f: function(){   return 1;  },  u: undefined,  n: null }

用擴展運算符和Object.assign()方法可以深拷貝對象

let obj1 = Object.assign({}, obj) obj[age] = 2; console.log(obj1); // let obj = { name: "a", age: 20, sex: false,user: {a: 20,n: "b},f: function(){return 1;},u: undefined,n: null}

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