Question

就像你们都知道一个按钮是一个按钮......点击，向上，向下，这样做，做到这一点。所以我写了一些默认按钮行为“class / object”。

外部默认button.js：

function Button(parent) {
    var self = this;
    this.enabled = true;
    this.visible = true;
    ...

    this.initialized = false;

    f_createButton(parent, self);

    this.initialized = true;
    ...
}

Button.prototype = {
    get initialized () { 
        return this._initialized; 
    },
    set initialized(bool){ 
        this._initialized = bool
        if(this.initialized === true) {
            ... do default stuff
        }
    },
    get enabled(){
        return this._enabled;
    },
    set enabled(bool){
        this._enabled = bool;
        if(document.getElementById(this.id)) { // is button defined?
            var mClassName = document.getElementById(this.id).children[0].className;
            document.getElementById(this.id).className = (this.enabled === false) ? "button button-Gray_disabled" : "button button-" + this.defaultStyle;
            document.getElementById(this.id).children[0].className = (this.enabled === false) ?  mClassName + "_disabled" : mClassName.replace("_disabled","");
        }
    }
}

function f_createButton("", obj) {
    .... create DOM element 
}

在html＆amp;中包含button.js按钮“类/对象”：

Object.defineProperty(Button.prototype,"buttonStyle", {
    get : function() {
        return this._buttonStyle;
    },
    set : function(str) {
        this._buttonStyle = str;
        if(this.id !== "undefined" && document.getElementById(this.id)) { // is button defined?
            document.getElementById(this.id).style.backgroundImage = 'url(Images/'+this.buttonStyle+'/buttons.png)';
        }
    }
});

这几乎可以工作，但它会杀死原始的Button初始化。

Object.defineProperty(Button.prototype,"initialized", {
    set : function( bool ) {
        this._initialized = bool;
        if(this.initialized === true) {
            this.buttonStyle = "NONE";
        }
    }
});

如何扩展原始的setter？

Answer 1

你问的问题似乎不寻常，但我们试试吧。首先，考虑一下这个基类，它将在你的外部js文件中：

// Constructor
function Button() {
    var self = this;
    var _initialized = false; // 'private' property manipulated by the accessors

    this.initialized = false;
    this.createButton();
    this.initialized = true;
}

// Default prototype
Button.prototype = { 
    createButton: function() {
        console.log(' create DOM element ');  
    }  
}

// Default getter/setter on prototype
Object.defineProperty(Button.prototype,"initialized", {
    set : function( bool ) {
        console.log('this is the original setter');
        this._initialized = bool;
        if(this._initialized === true) {
            console.log('do default stuff')
        }
    },

    get : function() {
        return this._initialized; 
    },

    configurable : true // IMPORTANT: this will allow us to redefine it
});

如果我理解你的要求，你想要重新定义initialized访问者（getter / setter），但仍然可以参考旧的访问者。也许有更好的方法可以做到这一点，但您可以将原始访问者复制到新的访问者中，然后重新定义它：

// Keep reference to the old accessors
var original = Object.getOwnPropertyDescriptor(Button.prototype, 'initialized');
Object.defineProperty(Button.prototype, "oldInitialized", {
    set : original.set,
    get : original.get
});

// Redefine getter and setter
Object.defineProperty(Button.prototype, "initialized", {
    set : function( bool ) {
        console.log('this is the new setter');
        this.oldInitialized = bool;
    },

    get : function() {
        return this._initialized; 
    }
});

以下是此代码：http://jsfiddle.net/aTYh3/。

扩展setter默认对象

1 个答案: