javascript对象文字-嵌套函数和"this"关键词 [英] javascript object literal - nested functions and the "this" keyword

问题描述

在下面的示例中，当调用functionA()时，this关键字引用了包含的对象，因此我可以访问其属性(例如theValue)

In the example below, when functionA() is invoked, the this keyword refers to the containing object, so I can access its properties (e.g. theValue)

我的问题:我如何从嵌套 functionB()内引用myObj的属性?

My question: How do I refer to properties of myObj from within the nested functionB()?

var myObj = {
    theValue: "The rain in Spain", 
    functionA: function() {
        alert(this.theValue);
    },
    moreFunctions: {
        functionB: function() {
            alert(????.theValue);
        }
    }
}

myObj.functionA(); 
myObj.moreFunctions.functionB();  

提前谢谢.

推荐答案

立即援救！

var myObj = (function () {
    var that = {
        theValue: "The rain in Spain", 
        functionA: function() {
            alert(this.theValue); // or that.theValue, both work here
        },
        moreFunctions: {
            functionB: function() {
                alert(that.theValue);
            }
        }
    };
    return that;
}()); // <-- immediate invocation !!

您可以进一步分解它:

var myObj = (function () {
    function functionA() {
        alert(that.theValue);
    }
    function functionB() {
        alert(that.theValue);
    }
    var that = {
        theValue: "The rain in Spain", 
        functionA: functionA,
        moreFunctions: {
            functionB: functionB
        }
    }
    return that;
}());

如果您熟悉OOP，则可以使用它来创建私有变量.

If you're familiar with OOP, you can use this to make private variables.

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