[Solved]-CombineReducers with Typescript returns error "Argument of type is not assignable to parameter of type 'ReducersMapObject'"-Reactjs

you're passing the object with all of helloreducer's exports instead of just the reducer. there's a couple of ways to fix it. you can select the reducer:

const reducer = combinereducers<storestate.all>({
    enthusiasm: enthusiasmreducer.enthusiasm
});

or import only the reducer:

import {enthusiasm} from './helloreducer';
..
const reducer = combinereducers({enthusiasm});

or add export default enthusiasm; to helloreducer.tsx and change the import to

import enthusiasmreducer from './helloreducer';