Best pattern for chaining dependent actions (Question) about redux-promise-middleware

[tomatau]

Maybe this? (with latest version)

export function createAndStart(name) {
  return (dispatch) => {
    dispatch({
      type: CREATE_AND_START,
      payload: {
        promise: new Promise(async (resolve, reject) => {
          await dispatch(create(name)).payload.promise
          await dispatch(start()).payload.promise
          resolve(push('/start'))
        })
      }
    });
  };
}

Have a look at our tests to get more of an idea of the return from dispatch calls when using a promise-middleware-action

[pburtchaell]

I'm busy for the rest of the week. I'll get back to you this weekend when I have some more time to read through your question to give you a worthwhile answer!

[baronnoraz]

Thanks! Sorry to be a bother, I really want to learn the/a proper way to do things. I'm grateful for the willingness to help.

[rkoberg]

I was looking for a way to do this type of thing as well. This works, but was wondering if there was a better way:

return ({fetch, settings: {firebaseUrl}}) => {
    return ({
      type: 'LOAD_PROFILE_USER',
      payload: {
        promise: fetch(`${firebaseUrl}/users/${slug}.json`)
          .then(response => response.json())
          .then(response => (users.viewer && users.viewer.slug === response.slug) ?
            Promise.resolve(loadProfileSettingsForm(response)) :
            Promise.resolve(true))
          .catch(err => {
            throw err;
          }),
      }
    });
  };

[rkoberg]

Also, if there is some way to do this with aysnc/await?

[baronnoraz]

@tomatau Thank you!! That worked perfectly. I truly appreciate the help, and I'll be sure to dig into the tests to learn more.

@rkoberg Hopefully this example using async/await helps you too...

[rkoberg]

Sure, but I just moved it to a separate async function (example below). Using Este, it takes care of dispatch for actions:
https://github.com/este/este/blob/master/src/common/configureStore.js#L23
https://github.com/este/este/blob/master/src/common/lib/injectDependencies.js

However, it just uses the dispatch function (not always a promise). What is the benefit of appending .payload.promise? I want access to the data to transform for the reducer. And I am not clear what you are doing with resolve(push('/start')). What is that for?

Here is what I am doing:

async function _login(firebase, fields) {
  try {
    const authData = await firebase.authWithPassword(fields.toJS());
    const userData = await getUserFromAuthData(firebase, authData);
    return {authData, userData};
  } catch (err) { //eslint-disable-line brace-style
    throw err;
  }
}

[baronnoraz]

@rkoberg the resolve(push('/start')) bit was just for my specific example. I needed to redirect upon completion of the second action.

[tomatau]

@rkoberg

What is the benefit of appending .payload.promise?

The return from dispatch when passed a promise action is an action object with the promise available at payload.promise, this allows you to await for the promise to be resolved, following @baronnoraz question and code.

I tend to move my async calls into separate functions and avoid action creators depending on each other.

[rkoberg]

OK. I have setup the firebase functions to return a promise. authWithPassword resolves into authData first. Then, async getUserFromAuthData has an await inside of it (to another Promisified firebase function). It resolves and all the data is sent in the return to the reducer. In other words, I don't seem to need .payload.promise -- wondering if I am somehow doing something wrong that currently results in the correct result.

[tomatau]

The example I posted was using actionCreator functions inside an actionCreator and awaiting on dispatch calls, check the OP for the API of the functions used in the example code I posted.

[pburtchaell]

@rkoberg I am going to close this since we resolved the OP's question. Would you mind creating a new issue? I'm happy to help.

[rkoberg]

I think we are good.

[artemjackson]

One more example:

/*
 * redux-thunk + redux-promise-middleware + redux-actions
 */
const _createAndStart = createAction(CREATE_AND_START,
  async (name, { dispatch }) => {
    await dispatch(create(name));
    await dispatch(start());
    await dispatch(push('/start'));
  });

export const createAndStart = (name) =>
  (dispatch) => dispatch(_createAndStart(name, { dispatch }));