Function that returns Preact component causes TypeScript “private name” error

I maintain a library for React and Preact. The library consists of a function that returns a class component. With React plus @types/react, each instance of the factory receives a generic instance of the React Component interface with my additions. With Preact, the TypeScript compiler complains about a private name:

[ts] Exported variable 'Block' has or is using private name 'JsxstyleComponent'.

It’d be super neat if Preact’s Component type definition behaved the same way that React’s Component type definition did in this regard.

The relevant bits of the factory function:

function factory(displayName: string, defaultProps?: any) {
  // ...
  return class JsxstyleComponent extends preact.Component<any> {
    //...
  }
}

const Block = factory('Block', { display: 'block' });

export const Block;

Output type defs from the React version:

export declare const Block: {
    new <P>(props: JsxstyleProps<P>): {
        className: string | null;
        component: AnyComponent<JsxstyleProps<P>>;
        componentWillReceiveProps(props: JsxstyleProps<P>): void;
        render(): JSX.Element;
        setState<K extends never>(f: (prevState: Readonly<{}>, props: JsxstyleProps<P>) => Pick<{}, K>, callback?: (() => any) | undefined): void;
        setState<K extends never>(state: Pick<{}, K>, callback?: (() => any) | undefined): void;
        forceUpdate(callBack?: (() => any) | undefined): void;
        props: Readonly<{
            children?: React.ReactNode;
        }> & Readonly<JsxstyleProps<P>>;
        state: Readonly<{}>;
        context: any;
        refs: {
            [key: string]: React.ReactInstance;
        };
    };
    defaultProps: Dict<React.ReactText> | undefined;
    displayName: string;
};

For Preact, I have to manually define a JsxstyleComponent type.

The referenced functions live here:

• React version
• Preact version

I’m still wrapping my head around TypeScript but I’m going to do some digging/reading so I can whip up a PR.

[marvinhagemeister]

@meyer That’s awesome! We’re currently in the process of cutting a new release 🎉

[meyer]

@marvinhagemeister I finally got a second to take a look, and it looks like my original issue has been fixed with the updated types. Thanks!