这个Backbone TodoMVC示例中的这些模式是什么 [英] What are these patterns in this Backbone TodoMVC example

问题描述

查看 todomvc主干代码示例. js/fold中的结构:

Looking into the todomvc backbone codes example. The structure in the js/ fold:

├── app.js
├── collections
│   └── todos.js
├── models
│   └── todo.js
├── routers
│   └── router.js
└── views
    ├── app-view.js
    └── todo-view.js

app.js

var app = app || {};
$(function () {
    'use strict';
    // kick things off by creating the `App`
    new app.AppView();
});

collections/todos.js

collections/todos.js

var app = app || {};

(function () {
    'use strict';
    var Todos = Backbone.Collection.extend({
    model: app.Todo,
    app.todos = new Todos();
})();

models/todo.js

models/todo.js

var app = app || {};

(function () {
    'use strict';
    app.Todo = Backbone.Model.extend({
    });
})();

views/app-view.js

views/app-view.js

var app = app || {};
(function ($) {
    'use strict';
    app.AppView = Backbone.View.extend({
})(jQuery);

我有两个问题:

1. 为什么每个文件中都var app = app || {}?

$(function(){})，(function(){})()和(function($))(jQuery)有什么区别?

推荐答案

1. app变量是全局变量，并且封装了整个Backbone应用程序，以最大程度地减少全局命名空间污染. 此处，您可以找到有关命名空间模式的更多详细信息.

1. app variable is global and encapsulates entire Backbone application to minimize global namespace pollution. Here you can find more details about Namespacing Patterns.

var app = app || {}尚未初始化，则使用新的空对象初始化全局app变量.否则它将保持不变.

var app = app || {} initializes global app variable with new empty object if it is not initialized yet. Otherwise it will be untouched.

功能:

• $(function(){})是jQuery $(document).ready(function(){})的快捷方式. 文档
• (function(){})()是没有参数的立即调用的函数表达式(IIFE)
• (function($){ /* here $ is safe jQuery object */ })(jQuery)是具有参数的IIFE-jQuery对象将作为$传递到该匿名函数中

• $(function(){}) is a shortcut for jQuery's $(document).ready(function(){}). Docs
• (function(){})() is an Immediately-invoked function expression (IIFE) without parameters
• (function($){ /* here $ is safe jQuery object */ })(jQuery) is IIFE with parameter - jQuery object will be passed as $ into that anonymous function

$(function() {
  console.log("Document ready event");
});

$(document).ready(function() {
  console.log("Document ready event");
});

(function() {
  console.log("Immediately-invoked function expression without parameters");
})();

(function($) {
  console.log("Immediately-invoked function expression with parameter. $ is a jQuery object here:");
  console.log($.fn.jquery);
})(jQuery);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

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