The NGRX reducers

eth.reducers.ts

import { GET_ACCOUNTS_SUCCESS, SELECT_ACCOUNT, AccountsActions } from './eth.actions';

export interface State {
   selected: string,
   accounts: string[]
}

const initialState: State = {
   selected: null,
   accounts: []
}

export const reducers = (state = initialState, action: AccountsActions): State => {
   switch (action.type) {
       case (GET_ACCOUNTS_SUCCESS): {
           return {...state, accounts: action.payload };
       };
       case (SELECT_ACCOUNT): {
           return {...state, selected: action.payload };
       };
       default: {
           return state;
       }
   }
}

/**
* Ethereum Global State
*/
export interface EthState {
   eth: State
}

export const ethReducer: ActionReducerMap<EthState> = {
   eth: reducers
};