some boilerplate

async_reducer_factory.js

const asyncReducerFactory = (name) => {
  return (state = { data: null, isLoading: false, error: null }, action) => {
    switch (action.type) {
      case `FETCH_${name}_STARTED`:
        return { data: null, isLoading: true, error: null };
      case `FETCH_${name}_SUCCESS`:
        return { data: action.payload, isLoading: false, error: null };
      case `FETCH_${name}_ERROR`:
        return { data: null, isLoading: false, error: action.payload };
      default:
        return state;
    }
  };
};

gistfile1.txt

const data = asyncReducerFactory('DATA');