Question

我希望基类与子类共享其成员变量，我该怎么做？

示例代码：

var register = function(f){
    setTimeout(function(){
        f('123');
    }, 5000);
};

var base = function(){
    var self = this;

    this.objects = [];

    this.events = {
        token : register(function(data){
             self.objects.push(data); //THIS WONT MODIFY THE child VERSION OF objects, how do I do that??
        })
    };
};

var child = function(){
    var self = this;

    this.objects = [2, 3, 4];
};
// child inherits from base
child.prototype = new base;
child.prototype.constructor = child;
child.prototype.parent = base.prototype;

var d = new child();
var e = new child();

setTimeout(function(){
    $('body').html(d.objects.join(",") + " " + e.objects.join(","));
    //prints out: "2,3,4 2,3,4" i want: "2,3,4,123 2,3,4,123"
}, 6000);

正如您所看到的，基类具有自己的对象实现，并且与子版本分开。我该如何解决这个问题？

小提琴：http://jsfiddle.net/8094g8ta/

Answer 1

您需要做的是让子构造函数调用父构造函数，以便为每个子进程运行父级初始化：

var child = function () {
    base.call(this);

    this.objects.push(2, 3, 4);
};

一旦你有了这个，使用new base创建子原型是没有意义的，因为它是多余的，事实上，调用构造函数来创建原型现在已经过时了。相反，请使用Object.create()：

// child inherits from base
child.prototype = Object.create(base.prototype);

全部放在一起：

var register = function(f) {
    setTimeout(function() {
        f('123');
    }, 5000);
};

var base = function() {
    var self = this;

    this.objects = [];

    this.events = {
        token: register(function(data) {
            self.objects.push(data);
        })
    };
};

var child = function() {
    base.call(this);

    this.objects.push(2, 3, 4);
};
// child inherits from base
child.prototype = Object.create(base.prototype);
child.prototype.constructor = child;
child.prototype.parent = base.prototype;

var d = new child();
var e = new child();

setTimeout(function() {
    $('body').html(d.objects.join(",") + " " + e.objects.join(","));
}, 6000);

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如何在javascript中实现基本成员？

1 个答案: