Example of a more complex request middleware

sendRequestMiddleware.js

import * as t from '@/actions/types';
import ajax from '@/adapters';
import getEndpoint from '@/constants/endpoints';

export default store => next => async action => {
  const { type, payload } = action;

  if (type === t.SEND_REQUEST) {
    const {
      data,
      entity,
      method,
      name,
      onSuccess = [],
      onError = [],
      onFinally = [],
    } = payload;
    
    const { headers, url } = getEndpoint(name, entity);
    const token = getAuthToken(store.getState());
    
    try {
      const response = await ajax({
        data,
        headers,
        method,
        token,
        url,
      });

      onSuccess.forEach(method => method(response));

    } catch(error) {
      onError.forEach(method => method(error));

    } finally {
      onFinally.forEach(method => method());
    }
  }

  next(action);
};