typescript - 无法在 Typescript 中定义类类型

Question

我正在尝试在 Typescript 中定义“定义”类型。定义可以是类构造函数或对象 - 稍后我会这样做:

 if (this._isConstructor(definition)) {
  return new definition(...args); // is a class - instantiate it
 }

return definition; // is just an object - return it

我的类型定义为:

type Definition = {
  new (arg?: object): object | object
}

这似乎有效。然而，它看起来很难看，我想把它分成:

type Definition = {
 Cstruct | object
}

type Cstruct = new (arg?: object): object

然而那是呻吟

Cannot use 'new' with an expression whose type lacks a call or construct signature

尝试“新建”它时。

Answer 1

使用 type guard 的解决方案:

type Definition = Cstruct | object
type Cstruct = {new (arg?: object): object}

function isConstructor(def: Definition): def is Cstruct {
  // Here implement your test and return true or false
  return true 
}

function getObject(def: Definition, args = []) {
  if (isConstructor(def))
    return new definition(...args);
  return def;
}