Backbone.js: _.bindAll() 初始化 - 为什么使用它? [英] Backbone.js: _.bindAll() in initialize - why is this used?

问题描述

我一直在查看一些基于backbone.js 的应用程序示例.我注意到在一些(例如这个例子 下面)使用下划线函数 _.bindAll() :

I've been looking at some examples of backbone.js based application. I notice that in some (such as this example below) the underscore function _.bindAll() is used:

 initialize: function (args) {
        _.bindAll(this, 'changeTitle');
        this.model.bind('change:title', this.changeTitle);
    },

而在其他应用程序中(例如下面的 todo 应用)不:

whereas in others (such as the todo app below) do not:

initialize: function() {
  this.model.bind('change', this.render, this);
  this.model.bind('destroy', this.remove, this);
},

_.bindAll() 在这种情况下的目的是什么，是否有必要?

What is the purpose of _.bindAll() in this context, and is it necessary?

推荐答案

_.bindAll() 将命名函数中的 this 更改为始终指向该对象，因此你可以使用this.model.bind().请注意，在您的第二个示例中，第三个参数被传递给 bind();这就是为什么在这种情况下不需要使用 _.bindAll() .一般来说，最好将模型上的任何方法用作事件回调，以便您可以更轻松地引用this.

_.bindAll() changes this in the named functions to always point to that object, so that you can use this.model.bind(). Notice that in your second example, a third argument is passed to bind(); that's why using _.bindAll() isn't necessary in that case. In general, it's a good idea to use for any methods on the model that will be used as callbacks to events so that you can refer to this more easily.

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