Listing 1: Loading Reducer

reducer.ts

// Reducer

export default (state: LoadingState = {}, action: Action<any>): LoadingState => {
  const { type } = action;
  const matches = /(.*)\/(REQUEST|SUCCESS|FAILURE)/.exec(type);

  // Ignore non-routine actions:
  //   A routine action should have one of three suffixes: 
  //   ['/REQUEST', '/SUCCESS', '/FAILURE']
  if (!matches) return state;

  const [, routineType, status] = matches;
  return {
    ...state,
    // Set loading state to true only when the status is "REQUEST"
    //    Otherwise set the loading state to false
    [routineType]: status === 'REQUEST'
  };
};