// 扩展运算符 — 推荐
const arr = [1,2,3]
const copyArr = [...arr]
// ES5
var arr = [1, 2, 3]
var len = arr.length
var copyArr = []
for (var i = 0; i < len; i += 1) {
copyArr[i] = arr[i]
}
// 扩展运算符 — 推荐
const arr = [1,2,3]
const copyArr = [...arr]
// ES5
var arr = [1, 2, 3]
var len = arr.length
var copyArr = []
for (var i = 0; i < len; i += 1) {
copyArr[i] = arr[i]
}