JS arguments parameter usage and explanation

One 、arguments Parameter Introduction

arguments, It is js An object built into a function in , The values of the actual parameters of the execution function method are stored in arguments in ;

To get these arguments , It needs to be like an array , Use subscript / Index to locate each value , But it can't be said to be an array , Because it has other properties , Such as callee;

And you can't use it shift、push、join Other methods .

Named parameters that do not pass values are automatically assigned undefined;

arguments.length---- Number of parameters

arguments.callee()--- Adjust the Commission itself

Two 、 Use cases

Case study 1：

        function show() {
            console.info(arguments);
            //arguments.callee()
        }
        show();
        show(1, 2);
        show(window, 1)

 

Case study 2：

        function sum() {
            var result = 0;
            for (