數(shù)組對(duì)象在JavaScript中默認(rèn)是引用類型。顧名思義、它是引用實(shí)際值，而自身不是實(shí)際值。由于這個(gè)原因，使用賦值操作（=）拷貝數(shù)組只是拷貝原始值的引用而不是實(shí)際的值。
在本文中，我們將介紹用JavaScript實(shí)際復(fù)制數(shù)組的5種方法。

1、擴(kuò)展運(yùn)算符

let clubs = ['Chelsea', 'Liverpool', 'Mancity', 'Real Madrid']
console.log(clubs)

//Create a clone Es6 way
let clonedClubs = [...clubs]
console.log(clonedClubs)

2、for() 循環(huán)

let clubs = ['Chelsea', 'Liverpool', 'Mancity', 'Real Madrid']
clonedClubs = [];
for (i = 0; i < clubs.length; i++) {
  clonedClubs[i] = clubs[i];
}
console.log(clonedClubs)

3、Array map()

let clubs = ['Chelsea', 'Liverpool', 'Mancity', 'Real Madrid']
cloning = (i) => i;

clonedClubs = clubs.map(cloning)
console.log(clonedClubs)

4、Array filter()

let clubs = ['Chelsea', 'Liverpool', 'Mancity', 'Real Madrid']

clonedClubs = clubs.slice();
console.log(clonedClubs)

4、Array slice()

let clubs = ['Chelsea', 'Liverpool', 'Mancity', 'Real Madrid']

clonedClubs = clubs.slice();
console.log(clonedClubs)