React-Redux: typescript types in selectFeatureFlag seem off

[Jan Prieser]

Describe the bug
ts(2345) Argument of type 'AppState' is not assignable to parameter of type 'Flags'.

To Reproduce
given i have a setup like this:

import { selectFeatureFlag } from '@flopflip/react-redux';

type AppState  = { 
  ...otherApplicationsStateSlices;
  [FLOPFLIP_STATE_SLICE]: Flags;
};

const mapStateToProps = (state: AppState) => ({
  someOtherState: state.someOtherState,
  isFeatureOn: selectFeatureFlag('fooFlagName')(state),
});

export default connect(mapStateToProps)(FooComponent);

Then i get the above mentioned typescript error.

Workaround is ugly and breaking type safety:
isFeatureOn: selectFeatureFlag('fooFlagName')((state as any) as Flags),

Expected behavior
Have another Type for the state in the definitions instead of :
export declare const selectFlag: (flagName: string) => (state: Flags) => string | boolean;
see https://github.com/tdeekens/flopflip/blob/master/packages/react-redux/modules/ducks/flags/flags.ts#L47

Is there another way to use this selector with typescript which i just didn't see?

[Tobias Deekens]

Hi,

thanks for reporting! Sorry for the issue with the typing I am personally not using the Redux package so I didn't spot this myself but wanted to provide it for the communicaty. I am not aware of another way of using the selector in a type safe manner. I think calling the state flags is false? Maybe just a super set with at least flags?

[Jan Prieser]

it may work with just (state: State), similar to https://github.com/tdeekens/flopflip/blob/master/packages/react-redux/modules/ducks/flags/flags.ts#L44

[Tobias Deekens]

Thanks. Changed that and published a canary (automatically from master). You can try the build with the version: 8.1.3-next.5 in your package.json. Let me know if this works for you. Thanks.

[Jan Prieser]

unfortunately this didn't work
type 'AppState' has no properties in common with type 'State'.ts(2559)

my guess now is, it would need an exposed type with the [FLOPFLIP_STATE_SLICE]: flopflipReducer, somehow involved.

[Tobias Deekens]

Yeap. Ok, will have a look later when I find time. If you have a clue already: a PR would be welcome :)

[Jan Prieser]

the fix worked, thanks for the fast response

[Tobias Deekens]

Published:

Successfully published:

• @flopflip/react-redux@8.1.3
• @flopflip/splitio-adapter@1.3.14

Thanks a lot for your contributions!