Question

我正在尝试创建一个动态构建自己的getter和setter的对象：

function Person( properties ) { // 'properties' is an object literal

    this._private = properties; // private by convention

    for ( key in this._private ) {

        this[key] = function() {

            return this._private[key];
        }
    }
}

我希望，这会产生类似的结果：

var jack = new Person({

    working:true,
    age:33,
    gender:'male'
});

jack.working() --> true
jack.age() --> 33
jack.gender() --> 'male'

问题是，它总是返回'男性'，如下所示：

jack.working() --> 'male'
jack.age() --> 'male'
jack.gender() --> 'male'

我缺少什么？哦，这只是一个概念证明。我知道这不是用JavaScript创建getter和setter的完美解决方案。

Answer 1

你有一个经典的范围界定问题。创建一个新函数来创建key的范围：

function Person(properties) { // 'properties' is an object literal
    var key;

    this._private = properties; // private by convention
    this.buildGetter = function (key) {
        this[key] = function () {
            return this._private[key];
        }
    };
    for (key in this._private) {
        this.buildGetter(key);
    }
}

示例： http://jsfiddle.net/SEujb/

Answer 2

每个人都说eval是邪恶的，但有时却无法避免：

function Person( properties ) { // 'properties' is an object literal

    this._private = properties; // private by convention

    for ( key in this._private ) {

        eval("this[key] = function() { return this._private['"+key.toString()+"'];}");
    }
}

jsFiddle：http://jsfiddle.net/pitaj/9sWbe/1/

动态Getter和Setter - 为什么这不起作用？

2 个答案: