是这些骨干/下划线.bind（）方法之间的区别？ [英] What is the difference between these Backbone/Underscore .bind() methods?

问题描述

window.SomeView = Backbone.View.extrend({
    initialize1: function() {
        _.bindAll(this, 'render');
        this.model.bind('change', this.render);
    },

    initialize2: function() {
        this.model.bind('change', _.bind(this.render, this));
    },

    initialize3: function() {
        _.bind(this.render, this);
        this.model.bind('change', this.render);
    },
});

随着一些SO成员的帮助下，我能得到我的测试项目有约束力的工作方法和initialize1 initialize2;我不明白的是为什么initialize3不起作用？

With help from some SO members, I was able to get my test project working with binding methods initialize1 and initialize2; what I don't understand is why initialize3 doesn't work?

文件： _.bind（函数，对象[*参数]）

推荐答案

有三个主要的差别; _。结合 一次只适用于一种方法，使钻营，并返回绑定的功能（这也意味着你可以使用 _绑定上一个匿名函数）：

There are three main differences; _.bind only works on one method at a time, allows currying, and returns the bound function (this also means that you can use _.bind on an anonymous function):

绑定的功能到对象，这意味着当函数被调用时，中的这个的将是在对象的值。或者，绑定的参数到功能以pre-填充它们，也被称为钻营

Bind a function to an object, meaning that whenever the function is called, the value of this will be the object. Optionally, bind arguments to the function to pre-fill them, also known as currying.

_。bindAll 结合众多的命名马上方法，不允许钻营，并绑定他们就地：

whereas _.bindAll binds many named methods at once, doesn't allow currying, and binds the them in-place:

绑定了一些在对象的方法，由指定的方法名后，在每当他们调用该对象的上下文中运行。

Binds a number of methods on the object, specified by methodNames, to be run in the context of that object whenever they are invoked.

所以，code这两大块大致相当于：

So these two chunks of code are roughly equivalent:

// Bind methods (not names) one a time.
o.m1 = _.bind(o.m1, o);
o.m2 = _.bind(o.m2, o);

// Bind several named methods at once.
_.bindAll(o, 'm1', 'm2');

但没有 bindAll 等价于：

f = _.bind(o, o.m1, 'pancakes');

这使得 F（）同 o.m1（'煎饼'）（这是<一个HREF =htt​​p://en.wikipedia.org/wiki/Currying>钻营）。

所以，当你这样说：

_.bindAll(this, 'render');
this.model.bind('change', this.render);

您要绑定的方法渲染有一个这个相匹配的电流这个然后你结合 this.render 来的变化事件 this.model 。

You're binding the method render to have a this that matches the current this and then you're binding this.render to the change event on this.model.

当你这样说：

this.model.bind('change', _.bind(this.render, this));

您在做同样的事情。而这个：

You're doing the same thing. And this:

_.bind(this.render, this);
this.model.bind('change', this.render);

因为你丢掉的返回值_不起作用。结合（即你扔掉绑定功能）。

doesn't work because you're throwing away the return value of _.bind (i.e. you throw away the bound function).

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