Typescript - forward和useref

Question

我有两个组件：

const ComponentOne = () => {
   const a = React.useRef<ComponentTwo>(null);
                // ^^^^^^^^^^ throws error - ComponentTwo refers to a value but used as type here
   const fn = () => {
      a.current.open(); // how to type it so typescript knows than open() is a function

      a.current.awdokawd(); // typescript should throw error here
   };

   return (
      <ComponentTwo ref={a} />
   );
}

const ComponentTwo = React.forwardRef((props, ref: React.RefObject<What here?>) => {
                                                            // ^^^^ what to type here?
   React.useImperativeHandle(ref, () => ({
      open: () => {
         console.log('hey');
      },
   }));

   return (
      ...
   );
});

如你所见，我不确定要用useRef输入什么，所以typescript可以正确地识别组件及其方法。我也不确定要用forwardRef输入什么。

谢谢!

Answer 1

您只需为ref声明一个新类型：

interface ComponentTwoRef {
    open(): void;
}

const ComponentOne = () => {
   const a = React.useRef<ComponentTwoRef>(null);

   const fn = () => {
      a.current.open();

      a.current.awdokawd(); // typescript should throw error here
   };

   return (
      <ComponentTwo ref={a} />
   );
}

const ComponentTwo = React.forwardRef((props, ref: React.RefObject<ComponentTwoRef>) => {

   React.useImperativeHandle(ref, () => ({
      open: () => {
         console.log('hey');
      },
   }));

   return (
      ...
   );
});