Redux Toolkit

createReducer

https://redux-toolkit.js.org/api/createReducer

import { createReducer } from '@reduxjs/toolkit';

createReducer(...)
builder.addCase(actionCreator, reducer)

createAction

https://redux-toolkit.js.org/api/createAction

import { createAction } from '@reduxjs/toolkit';

export const increment = createAction('counter/increment')
actionCreator.match