Javascript：在该对象中调用对象方法 [英] Javascript: Calling object methods within that object

问题描述

实现以下目标的最佳设计模式是什么（不起作用）？

What is the best design pattern for achieving the following (which doesn't work)?

var obj = (function() {

  // code defining private variables and methods

  var _obj = {
    property: value,
    method1: function() {
      // do stuff
    },
    method2: function() {
      // use property
      var prop = _obj.property; // obviously doesn't work
      // call method1
      obj.method1(); // "obj" not finished being defined yet!
    }
  };

  // obviously now I could do...
  var prop = _obj.property;

  return _obj;

})();

// and I could now do...
obj.method1();

我认为应该有效的变体是

A variation which I think should work is

var obj = (function() {

  var property = value,
      method1 = function() {
        // do stuff
      },
      method2 = function() {
        // use property
        var prop = property;
        // call method1
        method1();
      },
      _obj = {
        property: property,
        method1: method1,
        method2: method2
      };

  return _obj;

})();

同样，对于要用 new创建的对象，它是如何工作的运营商？在构造函数本身中，您可以编写 this.method（）。但是如果你想保持构造函数很小，只定义那些可能在创建时自定义的东西，然后在原型中定义其余的东西呢？ （这似乎是常见的模式。）原型中的属性/方法可以以任何方式进行交互吗？

Similarly, how does it work for objects meant to be created with the new operator? Within the constructor function itself you can write this.method(). But what if you want to keep the constructor small, only defining those things which will likely be customized upon creation, and then defining the rest in the prototype? (This seems to be the common pattern.) Can the properties / methods within the prototype interact in any way?

var MyObj = function(name) {
  this.name = name;
};

var obj = new MyObj('Bob');

MyObj.prototype = {
  called_often: function() {
    // lots more code than just the following
    return document.getElementById('someID').value;
  },

  global_default: 'value', // can be changed, so need to pull value when run

  does_stuff: function(value) {
    var str = global_default + value, // can't access global_default on its own
        input = MyObj.called_often(), // doesn't work; MyObj.prototype.called_often() DOES
        name = this.name; // 'this' used in the prototype doesn't work
                          // even within a created object
    return name + input + str;
  }
};

我确信每当遇到这个问题时，有更好的方法来实现我的结果。此代码不是特定于具体情况，只是说明了一般问题。因此，您无法为我遇到的特定情况提供替代方案。但也许你可以帮我整体思考。

I'm sure there's better ways to achieve my result whenever I run into this problem. This code isn't situation specific and just illustrates the general problem. So you won't be able to give me an alternative for those specific situations I run into. But maybe you can help my overall thinking.

推荐答案

嗯，从你的第一个例子开始：

Well, from your first example:

var _obj = {
    property: value,
    method1: function() {
      // do stuff
    },
    method2: function() {
      // use property
      var prop = this.property; 
      // call method1
      this.method1(); 
    }
  };

这是此值的用途。

现在，你不能做的是从对象文字语法的其他地方引用正在构建对象的属性。 （很难给出一个例子，因为它在语法上是不可能的。）如果你想这样做，你需要一个或多个单独的赋值语句。

Now, what you cannot do is refer to a property of an "under construction" object from elsewhere in the object literal syntax. (It's hard to give an example because it's just not syntactically possible.) In cases where you want to do that, you do need one or more separate assignment statements.

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