如何在 Typescript 中从构造函数（键）和类实例（值）声明 Map？

Question

以下代码与 component.constructor 有错误（实体构造函数以及 addComponent 和 removeComponent 方法）。

错误：'Function' 类型的参数不可分配给'typeof Component' 类型的参数。

如何声明 Map 其中 key = Class 构造函数，value = Class 实例？

declare class Component {
  constructor(...argArray: any[]);
}

// declare type MapOfComponents = Map<{new(): Component}, Component>
declare type MapOfComponents = Map<typeof Component, Component>

export default class Entity {
  static id = 1;

  id: number;
  components: MapOfComponents = new Map();

  constructor(components?: Array<Object>) {
    this.id = Entity.id++;

    components.forEach((component) => {
      this.components.set(component.constructor, component);
    });
  }

  addComponent(component: Component): this {
    this.components.set(component.constructor, component);
    return this;
  }

  removeComponent(component: Component): this {
    this.components.delete(component.constructor);
    return this;
  }

  hasComponent(ctr: typeof Component): boolean {
    return !!this.components.get(ctr);
  }

  getComponent(ctr: typeof Component): Object {
    return this.components.get(ctr);
  }
}

Answer 1

构造函数是一个函数，所以你可以这样写：

declare type MapOfComponents = Map<Function, Component>