🚧 常用TypeScript高级类型体操 🚧

函数签名

interface ObjectMap {
  button: HTMLButtonElement;
  input: HTMLInputElement;
  textarea: HTMLTextAreaElement;
}

function handleEvent(event: keyof ObjectMap) {
  console.log(event); // button, input, textarea
}

handleEvent('button'); // button

handleEvent('img'); // Error: 这里会发生类型错误

函数签名2

interface ObjectMap {
  button: HTMLButtonElement;
  input: HTMLInputElement;
  textarea: HTMLTextAreaElement;
}

function pushEvent<T extends keyof ObjectMap>(event: T, element: ObjectMap[T]) {
}

// 传入button类型，element会被推断为HTMLButtonElement类型
pushEvent('button', new HTMLButtonElement());

代理