Detailed explanation of the spread operator in ES6

This time I will bring you the expansion of ES6Operatordetailed explanation, what are the precautions for using the expansion operator of ES6, the following is a practical case, let's take a look.

//当传入的参数不确定时候;
function a(...arg) {
    console.log(arg[0]);
    console.log(arg[3]);
}
a(1, 23, 0);    　　　　//1  undefined
//其实也可以用这种替代; arguments本身是一个函数实参对象;
function a() {
    console.log(arguments[0]);
    console.log(arguments[3]);
}
a(1, 23, 0)            //1  undefined
//可以这么理解: ...arg取得了一个实参对象的每一项的值;并不是那个对象;
再看:
var arr0=["liu","hai"];
var arr1=[...arr0];
arr1.push("hello");
console.log(arr0);     //["liu","hai"]
console.log(arr1)      //["liu","hai","hello"]
发现并没有共享一份数据;
function test(aa,...args){
　　console.log(aa);
　　console.log(args[0]);
　　console.log(args[1]);
　　console.log(args.length);
}
test("first",1,2);       // first 1  2  2;

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to the php Chinese website Other related articles!

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