redux-future

FSA-compliant future monad middleware for Redux.

This is based on redux-promise.

npm install --save redux-future

Usage

import futureMiddleware from 'redux-future';

The default export is a middleware function. If it receives a future, it will dispatch the resolved value of the future (after forking the future). It will dispatch the error if one occures.

If it receives an Flux Standard Action whose payload is a future, it will fork and then either

• dispatch a copy of the action with the resolved value of the future.
• dispatch a copy of the action with the rejected value of the future, and set error to true.

Example

const result = new Future((reject, resolve) =>
  resolve([1, 2, 3, 4, 5, 6]));

const resultFiltered = result.map(
  R.compose(
    R.assoc('numbers', R.__, { type: 'FILTER_NUMBERS' })
  , R.filter(R.gt(3))
  )); // will hold [1, 2]

store.dispatch(resultFiltered);

Using in combination with redux-actions

Because it supports FSA actions, you can use redux-future in combination with redux-actions.

Example: Action creators

const result = new Future((reject, resolve) =>
  resolve([1, 2, 3, 4, 5, 6])
);

const resultFiltered = result.map(R.filter(R.gt(3))); // will hold [1, 2]

createAction('FILTER_ASYNC', () => resultFiltered);
// or
const filterAction = createAction('FILTER_ASYNC');
filterAction(resultFiltered);

Example: Future(IO)

You can use redux-future together with redux-io.

// futureIo :: Future(IO(String))
const futureIo = new Future((rej, res) => {
  const io = IO(() => location.href);

  setTimeout(() => res(io), 2000);
});

const action = createAction('FSA_ACTION');
store.dispatch(action(futureIo));

Related

Resources

Don't know what a future is? Read the following blog post or watch the video.

• A Monad in Practicality: Controlling Time
• Monad a day 2: Future

Libraries

• folktale data.task
• ramda-fantasy
• fantasy-future
• futurize - Turn callback-style functions or promises into futures
• redux-io - FSA-compliant IO monad middleware for redux
• redux-either - FSA-compliant Either monad middleware for redux