Read Store's Initial State in Redux Reducer

Question

Initial state in a Redux app can be set in two ways:

• pass it as the second argument to createStore (docs link)
• pass it as the first argum

Answer 1

I hope this answers your request (which I understood as initializing reducers while passing intialState and returning that state)

This is how we do it (warning: copied from Typescript code).

The gist of it is the if(!state) test in the mainReducer(factory) function

function getInitialState(): MainState {

     return {
         prop1:                 'value1',
         prop1:                 'value2',
         ...        
     }
}



const reducer = combineReducers(
    {
        main:     mainReducer( getInitialState() ),
        ...
    }
)



const mainReducer = ( initialState: MainState ): Reducer => {

    return ( state: MainState, action: Action ): MainState => {

        if ( !state ) {
            return initialState
        }

        console.log( 'Main reducer action: ', action ) 

        switch ( action.type ) {
            ....
        }
    }
}