js 数组合并

let arr1 = ['温情', '刘聪']
let arr2 = ['杨和苏', '邓紫棋']
let arr3 = ['周延']

1. arr1.concat(arr2, ······)

• es5 Array.concat() 合并两个数组, 返回新数组，不会改变原数组

arr = arr1.concat(arr2, arr3);
console.log(arr);  // ["温情", "刘聪", "杨和苏", "邓紫棋", "周延"]

2. […arr1, …arr2，······]

• es6 展开运算符(…)

arr = [...arr1, ...arr2, ...arr3];
console.log(arr);  // ["温情", "刘聪", "杨和苏", "邓紫棋", "周延"]

3. push(…arr)

• push 结合 ...[] 来实现, 会更改原数组

arr1.push(...arr2, ...arr3)
console.log(arr1);  // ["温情", "刘聪", "杨和苏", "邓紫棋", "周延"

适合两个数组，不适合多个数组的方法

1. for + push

for(let i in arr2) {
    arr1.push(arr2[i])
}
console.log(arr1);  // ["温情", "刘聪", "杨和苏", "邓紫棋"]

2. arr1.push.apply(arr1, arr2)

arr1.push.apply(arr1, arr2)
console.log(arr1);  // ["温情", "刘聪", "杨和苏", "邓紫棋"]

• 多个数组也可以用，不过只是多此一举