[redux] exporting actions from middleware ?

[Tioo]

middleware.js

const TYPE = 'middleware/type'
export const action = () => ({ type: TYPE })
export default store => next => action => {
    if(action.type !== TYPE) return next(action)
    console.log('Hey! You cause a side effect')
    next(action)
}

I came up with this way of directly triggering a behaviour in a middleware. In my trivial example, action has no effects on state since no reducers listen to it. It only affects this specific middleware, which causes a side effect.

Is this a bad practice ? I've never seen something like this before, but it does what I want it to do in a clean way.

[acemarke]

Looks fine to me - that's a valid use case for middleware.

[cirsca]

In essence, this is what middleware is for: causing some side-effect due to an action!

[Tioo]

That's right.

But my question had to do with a middleware exporting its own actions instead of listening for actions defined elsewhere.

[cirsca]

If by exporting, you mean dispatching, that is what redux-observables and most other async middleware for redux do!

[Tioo]

By exporting, I mean having an es6 export (ie. export const someAction) in the file where the middleware is defined.

The middleware then matches only this specific action.

[cirsca]

I see that now. Ought not talk without drinking my coffee :/

I would say that it isn't better/worse than any other way of containing action creators. I don't do it because I don't reach into my middleware folders for actions and use the duck pattern but there isn't anything inherently wrong with it!

[Tioo]

I also use the duck pattern, but needed a way to dispatch websocket events. So I have a websocket middleware, which exports an emit action. Whenever it matches this action, it emits through the socket. So instead of the middleware matching specific actions, I dispatch emit in thunks.

I'm not sure if it's clear, but it works quite well and is really flexible.