Typescript: `typeof React.Component` stopped working

[mikew]

TypeScript Version: 2.5.3

Code

class MyComponent extends React.Component<{}, {}> {
  render () {
    return null
  }
}

function thisTakesAComponent (component: typeof React.Component) {

}

thisTakesAComponent(MyComponent)

Expected behavior:
Should compile fine.

Actual behavior:

Argument of type 'typeof MyComponent' is not assignable to parameter of type 'typeof Component'.
  Type 'MyComponent' is not assignable to type 'Component<P, S>'.
    Types of property 'setState' are incompatible.
      Type '{ <K extends never>(f: (prevState: {}, props: {}) => Pick<{}, K>, callback?: (() => any) | undefi...' is not assignable to type '{ <K extends keyof S>(f: (prevState: S, props: P) => Pick<S, K>, callback?: (() => any) | undefin...'.
        Types of parameters 'f' and 'f' are incompatible.
          Types of parameters 'prevState' and 'prevState' are incompatible.
            Type '{}' is not assignable to type 'S'.

[andy-ms]

MyComponent is not of type typeof React.Component, it's of type typeof MyComponent. This probably used to work before #16368, since we ignored the generic type arguments before, which made them indistinguishable.
If you want a type of subclasses of React.Component, you could use something like { new(): React.Component<any, any> } -- of course this depends on how you plan to use the variable.

[mikew]

And what about for stateless functions? IE I don't want "a type of subclasses of React.Component", I want "something that will be rendered correctly with React.createElement".

[andy-ms]

I guess that depends on what react needs available on such a type -- I'm not familiar with the library so I couldn't tell you.

[mhegazy]

why not:

 function thisTakesAComponent <P>(component: React.SFC<P> | React.ComponentClass<P>) {
 }

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.

[samuelneff]

Not sure if this was applicable when originally asked, but now you can do this:

    function thisTakesAComponent(component: ReactType) {
    }