Remove empty meta objects from action
import isPromise from './isPromise';

const defaultTypes = ['PENDING', 'FULFILLED', 'REJECTED']

export default function promiseMiddleware(config={}) {
  const promiseTypes = config.promiseTypes || defaultTypes;
  return () => {
    return next => action => {
      if (!isPromise(action.payload)) {
        return next(action);
      }

      const { type, payload, meta={} } = action;
      const { promise, data } = payload;
      const [ PENDING, FULFILLED, REJECTED ] = meta.promiseTypes || promiseTypes;

      next({
        type: `${type}_${PENDING}`,
        payload: data,
        ...meta || {}
      });

      return promise.then(
        payload => next({
          payload,
          ...meta || {},
          type: `${type}_${FULFILLED}`,
        }),
        error => next({
          payload: error,
          error: true,
          ...meta || {},
          type: `${type}_${REJECTED}`,
        })
      );
    };
  }
}

import isPromise from './isPromise';

const defaultTypes = ['PENDING', 'FULFILLED', 'REJECTED']

export default function promiseMiddleware(config={}) {
  const promiseTypes = config.promiseTypes || defaultTypes;
  return () => {
    return next => action => {
      if (!isPromise(action.payload)) {
        return next(action);
      }

      const { type, payload, meta={} } = action;
      const { promise, data } = payload;
      const [ PENDING, FULFILLED, REJECTED ] = meta.promiseTypes || promiseTypes;

      next({
        type: `${type}_${PENDING}`,
        payload: data,
        meta
      });

      return promise.then(
        payload => next({
          payload,
          meta,
          type: `${type}_${FULFILLED}`,
        }),
        error => next({
          payload: error,
          error: true,
          type: `${type}_${REJECTED}`,
        })
      );
    };
  }
}
