ES6复制数组//合并数组concat()和rest

如果只是用=号连接数组的话,就是一个指向的复制,这两个数组会同时变化的

//复制数组

(方法一:)

var arr1=['a','b','c','d'];
var cc=arr1.concat();
cc[1]='yy';
console.log(arr1);//["a", "b", "c", "d"]
console.log(cc);//["a", "yy", "c", "d"]

(方法二:)

var arr1=['a','b','c','d'];
var  dd=[...arr1];
dd[0]='es6';
console.log(dd);//["es6", "b", "c", "d"]
console.log(arr1);//["a", "b", "c", "d"]

 

//合并数组

(方法一:)

var arr1=['a','b','c','d'];
var arr2=['d'];
var arr3=['e','f'];
var cc=arr1.concat(arr2,arr3);
console.log(cc);//["a", "b", "c", "d", "d", "e", "f"]



(方法二:)
 

var arr1=['a','b','c','d'];
var arr2=['d'];
var arr3=['e','f'];
var dd=[...arr1,...arr2,...arr3];
console.log(dd);//["a", "b", "c", "d", "d", "e", "f"]

 

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