合并数组 apply

var arr1=[1,2,3]
var arr2=[4,5,6]

Array.prototype.push.apply(arr1, arr2);
arr1 // [1, 2, 3, 4, 5, 6]

var newArr=arr1.concat(arr2)
newArr = [1, 2, 3, 4, 5, 6]

function f(x, y, z) {
console.log(arguments)
}
var args = [0, 1, 2];
f.apply(null, args);

var args=[1,2,3]

function f(x,y,z){
console.log(arguments)
}

f(...args)