Question

我的目标是从其他函数 Submain

的原型向 Main 函数的（this）上下文添加属性

function Main() {
   Submain.call(this);
   //from here I want to be able to use this.a, this.b, this.c, this.d
   //...Main code...
}

function Submain() {
   //this works fine
   this.a = 1;
   this.b = 2;

   //this does not work because of the context
   this.doThis();
}

Submain.prototype.doThis = function() {
   this.c = 3;
   this.d = 4;
}

那么，如何将 Submain 原型用于此目的？

Answer 1

如果我理解正确，您缺少的部分是设置Main构造函数的原型。人们通常会这样做：

Object.setPrototypeOf(Main.prototype, Submain.prototype);

然后你可以在构造函数中或从任何其他方法调用doThis创建的对象上的new Main：

var main = new Main();
console.log(main.c, main.d); // prints 3, 4

Answer 2

我必须将 Submain 原型合并到 Main 原型。

可以使用 Object.assign （ES6）完成此操作。

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如何将call（）与原型一起使用？

2 个答案: