打字稿接口和承诺返回一个对象/构造函数？

Question

我有一个返回类型的 Promise

person.ts

const personFactory: PersonFactory = (name, lastName) => ({ speak: () => console.log(`${name}:${lastName}`); });
const personPromise: Promise<PersonFactory | null> = Promise.resolve().then(function handler() { return personFactory });

export const loadPerson = (): Promise<PersonFactory | null> => {
  return personPromise;
};

index.ts

declare global {
  interface Metaverse {
    Person?: PersonFactory;
  }
}

export interface PersonClient {
    speak: (args: string) => void;
}

export type PersonFactory = (firstName: string, lastName: string) => PersonClient;

person.ts 和 index.ts 打包后放入 npm 包中。

测试 ts 项目 - index.ts

import { loadPerson } from '@person/library';

const load = async () => {
  const person = await loadPerson();

  if (person) {
    person('drag13', 'developer').speak('something');
  }
}

load()

// 或

(async function() {
 let person = await loadPerson();
 person("drag13", "developer").speak("this===is===a===message")
})()

-- 更新

我使用了 Drag13 的示例并将其打包成一个 npm。当我调用 loadPerson 时，控制台会打印出说话的字符串。

但是有一个打字稿错误提示

TS2349: This expression is not callable. Type 'PersonFactory' has no call signatures.

Answer 1

您定义了您的承诺应该return factory 或 null。但是在您的代码中，您没有返回任何内容。

正确的版本如下所示：

const personPromise: Promise<PersonFactory | null> = Promise.resolve().then(() => () => ({ speak: () => null }));

现在你可以这样使用：

(async function () {

    interface PersonClient {
        speak: (args: string) => void;
    }

    type PersonFactory = (firstName: string, lastName: string) => PersonClient;
    const personFactory: PersonFactory = (name, lastName) => ({ speak: () => `${name}:${lastName}` });
    const personPromise: Promise<PersonFactory | null> = Promise.resolve().then(function handler() { return personFactory });

    const person = await personPromise;

    if (person) {
        person('drag13', 'developer').speak('something');
    }

})()

为了让它发挥作用，我们：

• 定义函数personFactory
• 从then返回personFactory

现在可以使用了 - Playground