Typescript RefForwardingComponent not working

问题:

I am trying to make my component accept a ref.

I have a component like so:

const MyComponent: RefForwardingComponent<HTMLDivElement, IMyComponentProps> = (props, ref) => {
    return <div ref={ref}>Hoopla</div>
}

But when I try to pass a ref to is like so:

<MyComponent ref={myRef}></MyComponent>

... I get this error:

Property 'ref' does not exist on type 'IntrinsicAttributes & IMyComponentProps & { children?: ReactNode; }'.ts(2322)

What am I doing wrong?

回答1:

RefForwardingComponent is a render function, which receives props and ref parameters and returns a React node - it is no component:

The second ref argument only exists when you define a component with React.forwardRef call. Regular function or class components don’t receive the ref argument, and ref is not available in props either. (docs)

That is also the reason, why RefForwardingComponent is deprecated in favor of ForwardRefRenderFunction, which is functionally equivalent, but has a different name to make the distinction clearer.

You use React.forwardRef to turn the render function into an actual component that accepts refs:

import React, { ForwardRefRenderFunction } from 'react'

type IMyComponentProps = { a: string }
const MyComponentRenderFn: ForwardRefRenderFunction<HTMLDivElement, IMyComponentProps> =
    (props, ref) => <div ref={ref}>Hoopla</div>

const MyComponent = React.forwardRef(MyComponentRenderFn);
const myRef = React.createRef<HTMLDivElement>();

<MyComponent a="foo" ref={myRef} />

回答2:

Your code is right but you are missing a small detail.

When you use RefForwardingComponent you need to export the component wrapped with forwardRef

import React, { forwardRef, RefForwardingComponent } from 'react';

type IMyComponentProps = {}
const MyComponent: RefForwardingComponent<HTMLDivElement, IMyComponentProps> = (props, ref) => {
    return <div ref={ref}>Hoopla</div>
}

export default forwardRef(MyComponent);

回答3:

I think this is a bug in React's type definitions for RefForwardingComponent. You can work around this by adding the ref?: React.RefObject<HTMLDivElement> to your props. This will fix your compiler error.

try this:

type IMyComponentProps = {
    ref?: React.RefObject<HTMLDivElement>
}

I believe this requirement is a bug, because it should be added to the props for you by RefForwardingComponent. Putting it in your own props means that TypeScript will expect the props argument inside your function to contain the ref prop and I don't think it does. This however is not a big problem.

回答4:

Custom function components can't have 'ref' as a prop. You will have to give it a different name. 'yourRef', for example will be inside the props object.

<MyComponent yourRef={myRef}></MyComponent>

So to use the ref prop:

const MyComponent: RefForwardingComponent<HTMLDivElement, IMyComponentProps> = (props) => {
return <div ref={props.yourRef}>Hoopla</div>}

or you can descructure the props:

const MyComponent: RefForwardingComponent<HTMLDivElement, IMyComponentProps> = ({yourRef}) => {
return <div ref={yourRef}>Hoopla</div>}