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TypeScript React HOC using `forwardRef`
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import * as React from 'react'; | |
import { Component, ComponentClass, createRef, forwardRef, Ref } from 'react'; | |
const myHoc = <ComposedComponentProps extends {}>( | |
ComposedComponent: ComponentClass<ComposedComponentProps>, | |
) => { | |
type ComposedComponentInstance = InstanceType<typeof ComposedComponent>; | |
type WrapperComponentProps = ComposedComponentProps & { | |
wrapperComponentProp: number; | |
}; | |
type WrapperComponentPropsWithForwardedRef = WrapperComponentProps & { | |
forwardedRef: Ref<ComposedComponentInstance>; | |
}; | |
class WrapperComponent extends Component< | |
WrapperComponentPropsWithForwardedRef, | |
{} | |
> { | |
render() { | |
const { | |
forwardedRef, | |
wrapperComponentProp, | |
...composedComponentProps | |
} = this.props; | |
return ( | |
<ComposedComponent | |
ref={forwardedRef} | |
// We need a cast because: | |
// https://github.com/DefinitelyTyped/DefinitelyTyped/issues/32355 | |
// https://github.com/Microsoft/TypeScript/issues/28938#issuecomment-450636046 | |
{...composedComponentProps as ComposedComponentProps} | |
/> | |
); | |
} | |
} | |
return forwardRef<ComposedComponentInstance, WrapperComponentProps>( | |
(props, ref) => <WrapperComponent forwardedRef={ref} {...props} />, | |
); | |
}; | |
type MyComponentProps = { composedComponentProp: number }; | |
class MyComponent extends Component<MyComponentProps> {} | |
const ref = createRef<MyComponent>(); | |
const badRef = createRef<ComponentClass<{}>>(); | |
const MyComponentAfterHoc = myHoc(MyComponent); | |
// | |
// Tests | |
// | |
// should succeed: | |
<MyComponentAfterHoc composedComponentProp={1} wrapperComponentProp={1} />; | |
<MyComponentAfterHoc | |
composedComponentProp={1} | |
wrapperComponentProp={1} | |
ref={e => {}} | |
/>; | |
<MyComponentAfterHoc | |
composedComponentProp={1} | |
wrapperComponentProp={1} | |
ref={ref} | |
/>; | |
// should error: | |
<MyComponentAfterHoc | |
composedComponentProp={1} | |
wrapperComponentProp={1} | |
ref={badRef} | |
/>; | |
<MyComponentAfterHoc composedComponentProp={'1'} wrapperComponentProp={1} />; | |
<MyComponentAfterHoc composedComponentProp={'1'} wrapperComponentProp={'1'} />; | |
<MyComponentAfterHoc />; |
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