javascript函数后括号中的值 [英] Values in parentheses after javascript function

问题描述

我正在尝试重新设定我在SO上的答案中找到的一些Javascript代码。但我想首先更好地理解它的语法。它的大纲是：

I'm trying to re-purpose some Javascript code I found linked in an answer on SO. But I would like to understand its syntax better first. Its outline is:

(function (root, ns, factory) {
    // some code
} (window, 'detectZoom', function() {
    // some more code
}));

请参阅这篇文章以引用完整代码。

See accepted answer in this post for the reference to the full code.

我理解最终结果是如何实现的，但我不太清楚内部（...）块如何与第一个相关，或者它内部的逗号分隔列表告诉编译器。

I understand how the end-result is achieved, but I don't quite know how the inner (...) block relates to the first, or what the comma separated list inside it tells the compiler.

有人可以解释一下吗？谢谢。

Can someone explain? Thanks.

推荐答案

有一个匿名函数有三个参数（ root ， ns ， factory ）立即被调用。

There is an anonymous function taking three parameters (root, ns, factory) which is immediately invoked.

• root 取值`窗口。


• ns 取值'detectZoom'


• factory 获取回调函数的值（也是匿名的）

• root takes the value of`window.
• ns takes the value of 'detectZoom'
• factory takes the value of callback function (also anonymous)

解释：

(function (root, ns, factory) {
   // the body of the anonymous function
} (window, 'detectZoom', function() {
   // the body of the 'factory' callback
}));

要分解它，如何分四步获取此代码：

To break it apart, how to get to this code in four steps:

 1.
 // Anonymous function.
 (function (root, ns, factory) {/* body */});

 2.
 // Anonynmous function, immediately invoked
 (function (root, ns, factory) {/* body */})();  // parentheses mean it's invoked

 3.
 // Callback as a separate argument
 var cbk = function () {};
 (function (root, ns, factory) {/* body */})(window, 'detectZoom', cbk);

 4.
 // Callback as an anonymous function
 (function (root, ns, factory) {/* body */})(window, 'detectZoom', function () {});

您可以将代码重写为更详细：

You could rewrite your code to be more verbose:

var outer = function (root, ns, factory) {
  // the body
};

var callback = function () {
  // the body
};

outer(window, 'detectZoom', callback);

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