promise_middleware_redux

export function promiseMiddleware() {
    function isPromise(value) {
        return value && typeof value.then === 'function';
    }

    return next => action => {
        if (!isPromise(action.promise)) {
            return next(action);
        }

        const { types } = action;
        const promise = action.promise;
        const [ PENDING, FULFILLED, REJECTED ] = types;

        /**
     * Dispatch the first async handler. This tells the
     * reducer that an async action has been dispatched.
     */
        next({
            type: PENDING
        });

        /**
     * Return either the fulfilled action object or the rejected
     * action object.
     */
        return promise.then(
            response => next({
                response: JSON.parse(response.text).data || JSON.parse(response.text),
                type: FULFILLED
            }),
            error => next({
                error: JSON.parse(error.response.text).error,
                type: REJECTED
            })
        );
    };
}