Enable RemoteData to take a promise

[jackfranklin]

Under the hood right now Remote Data uses fetch directly, but in many real world apps (like the one I'd like to use this in!) this is a problem, because we use our own API client that has special headers, etc, etc set up.

Rather than pass all this into RemoteData it would be much better if along with calling fetch you could also give it a promise that should resolve or error accordingly.

Doing this would:

• give you a RemoteData that's immediately in the PENDING state (and not fire an onChange for the NOT_ASKED => PENDING transition
• If the promise resolves, we go to SUCCESS and provide whatever the promise resolved with as the data
• If it rejects, we go to FAILURE and provide the error data.

I think this should be a new method on RemoteData ? Could be something like:

// 1
import RemoteData from 'remote-data-js'

const myPromise = myHttpClient.get('/foo')
const customRemote = RemoteData.fromPromise(myPromise, {
  onChange: newRemote => {
     // either succeeded with the data or failed
  }
})
customRemote.isPending() => true

// OR:

const customRemote = RemoteData.fromPromise(myPromise).onChange(fn)

[jackfranklin]

@isaacseymour I feel like you might have thoughts :)

[jackfranklin]

Also if we did this it might be nice to hide the actual class under the hood and turn the top level API into:

import { withPromise, withFetch } from 'remote-data-js'

const remoteData  = withPromise(promise, { onChange })
const remoteData = withFetch(url, {onChange, fetchOptions, ...})

Would prevent more breaking changes in the future.

[joshhornby]

Hi @jackfranklin Any updates with this?

[jackfranklin]

No - not yet! PRs' welcome :)

[jackfranklin]

@joshhornby

You can now do import { withPromise } from 'remote-data-js'

Not yet got the fromFetch API (see README for current details).