Javascript函數的參數arguments

arguments
　　Description
　　　　在全部的函數中有一個arguments對象，arguments對象指向函數的參數，arguments object is an Array-like object，除了length，不具有數組的其餘屬性。
　　　　訪問： var a = arguments[0];
　　　　arguments能夠改變： arguments[1] = 'new value';
　　　　arguments轉換爲一個真實的數組：
　　　　　　var args = Array.prototype.slice.call(arguments);
　　　　　　var args = [].slice.call(arguments);
　　　　　　var args = Array.from(arguments);
　　　　　　var args = [...arguments];

　　Properties
　　　　arguments.callee
　　　　　　Reference to the currently executing function.
　　　　　　指向當前正在執行的函數的函數體。在匿名函數中頗有用。

function fun(){ console.log(arguments.callee == fun);//true
 console.log(arguments.callee); /* function fun(){ console.log(arguments.callee == fun);//true console.log(arguments.callee); } */ } fun();

var global = this; var sillyFunction = function(recursed) { if (!recursed) { return arguments.callee(true); } if (this !== global) { console.log('This is: ' + this); } else { console.log('This is the global'); } } sillyFunction();//This is: [object Arguments]

　　　　使用arguments.callee在匿名遞歸函數中：
　　　　　　一個遞歸函數必須可以指向它本身，經過函數名能夠指向本身，可是在匿名函數沒有函數名，因此使用arguments.callee指向本身。

function create() { return function(n) { if (n <= 1) return 1; return n * arguments.callee(n - 1); }; } var result = create()(5); console.log(result);// returns 120 (5 * 4 * 3 * 2 * 1)

　　　　arguments.caller
　　　　　　Reference to the function that invoked the currently executing function.這個屬性已經被移出了，再也不工做，可是仍然能夠使用Function.caller.

function whoCalled() { if (arguments.caller == null) console.log('I was called from the global scope.'); else console.log(arguments.caller + ' called me!'); } whoCalled();//I was called from the global scope.

function whoCalled() { if (whoCalled.caller == null) console.log('I was called from the global scope.'); else console.log(whoCalled.caller + ' called me!'); } whoCalled();//I was called from the global scope.

function whoCalled() { if (whoCalled.caller == null) console.log('I was called from the global scope.'); else console.log(whoCalled.caller + ' called me!'); } function meCalled(){ whoCalled(); } meCalled(); /* function meCalled(){ whoCalled(); } called me! */

　　　　arguments.length
　　　　　　Reference to the number of arguments passed to the function.
　　　　arguments[@@iterator]
　　　　　　Returns a new Array Iterator object that contains the values for each index in the arguments.

　　Examples

function myConcat(separator) { var args = Array.prototype.slice.call(arguments, 1); return args.join(separator); } myConcat(', ', 'red', 'orange', 'blue');// returns "red, orange, blue"

function bar(a = 1) { arguments[0] = 100; return a; } bar(10); // 10

function zoo(a) { arguments[0] = 100; return a; } zoo(10); // 100