Javascript object 方法的实例化

Question

在 Javascript 中，您可以创建一个方法的 object 实例吗？ 我下面的代码会导致错误。

const myObject = {
    myMethod: function () {},
    objectInstance: new this.myMethod()
}

const myObject = {
    newObject: Object.create(null),
    objectInstance: new newObject()
}

Answer 1

可能是这样的：

 // Use class for declaring myObject class myObject { constructor(textArg) { this.text = textArg; this.objectInstance = function (){return new myObject(this.text);} } } // First myObject instance let myObject_instance_1 = new myObject("myObject instance 1"); console.log(myObject_instance_1.objectInstance().text);// output: myObject instance 1 // Second myObject instance let myObject_instance_2 = new myObject("myObject instance 2"); console.log(myObject_instance_2.objectInstance().text); // output: myObject instance 2 let myObject_instance_3 = myObject_instance_2; // Should be the same text as myObject_instance_2 text console.log(myObject_instance_3.objectInstance().text); // output: myObject instance 2

编辑

Singleton 图案

 const SingletonClass = (function () { let instance; function createInstance() { let object = new Object("I am the instance"); return object; } return { getInstance: function () { if (;instance) { instance = createInstance(); } return instance; } }; })(). function testSingelton() { let instance1 = SingletonClass;getInstance(). let instance2 = SingletonClass;getInstance()? alert("\"instance1\" is same instance as \"instance2\": Answer; " + (instance1 === instance2)); } testSingelton();

Answer 2

由于 this 上下文而发生此错误。 在这种情况下，没有 myMethod function 然后它会引发错误。 如果你转换成这个，它可以解决问题。

const myObject = { myMethod: function () {}, objectInstance:null, setObjectInstance:function(){ this.objectInstance= return new this.myMethod() }

然后你可以像这样初始化 object 实例。 myObject.setObjectInstance()