在Typescript中，Object.prototype函数可以返回Sub类型实例吗? [英] in Typescript, can Object.prototype function return Sub type instance?

问题描述

我想编写类似

class Place {
  next: Place;
  get to() : Place {
    return this;
  }
}
let places : Place[]= [];
..

places[0].to.next = new Place();

有很多类似的类，所以我想为Object.prototype定义'to'属性.

There are many similar classes, so I want define 'to' property to Object.prototype.

Object.defineProperty(Object.prototye,"to",{
  get: function() {
    return this;
  }
});

但是由于类型'对象'不存在属性'next'

我可以使用Object.prototype函数或属性返回Typescript中的子类型吗?

Can I return subtype in Typescript with Object.prototype function or property?

推荐答案

Typescript不能精确建模所需的行为.

Typescript can't model exactly the beahavior you want.

我能想到的最接近的方法是使用方法而不是属性.对于方法，我们可以定义一个 this 参数并推断其类型并将其用作返回类型:

The closest I can think of is to use a method not a property. For methods we can define a this parameter and infer it's type and use it as the return type:

class Place extends Object{
  next: Place;
}
let places: Place[] = [];

interface Object{
  to<T>(this: T):T; 
}
Object.prototype.to = function () {
  return this;
};

places[0].to().next = new Place();

最简单的解决方案是对属性类型为多态 this 的所有此类对象实际使用基类:

The simplest solution would be to actually use a base class for all such objects with the property typed as polymorphic this:

class Base {
  get to(): this { return this; }
}
class Place extends Base{
  next: Place;
}
let places: Place[] = [];
places[0].to.next = new Place();

注意:污染全局 Object 似乎不是一个好主意，但最终这是您的要求.

Note: Polluting the global Object does not seem like a great idea but ultimately that is your call.

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