updux/docs/concepts.md

Updux concepts

effects

Updux effects are a superset of redux middleware. I kept that format, and the use of next mostly because I wanted to give myself a way to alter actions before they hit the reducer, something that redux-saga and rematch don't allow.

An effect has the signature

const effect = ({ getState, dispatch, getRootState, selectors}) 
                => next => action => { ... }

The first argument is like the usual redux middlewareApi, except for the availability of selectors and of the root updux's state.

Also, the function dispatch is augmented to be able to be called with the allowed actions as props. For example, assuming that the action complete_todo has been declared somewhere, then it's possible to do:

updux.addEffect( 'todo_bankrupcy',
    ({ getState, dispatch }) => next => action => {
        getState.forEach( todo => dispatch.complete_todo( todo.id ) );
    }
)