rxjs select stream

select-stream.js

export default function create({
  Observable,
  gridSelectStream,
  newEntityResolveStream,
  entityStoreStateStream
}) {
  const newEntitySelectStream = newEntityResolveStream
  .switchMap(function onSwitchMap(eventData) {
    return entityStoreStateStream
    .filter(function onFilter(entityStoreStateData) {
      return entityStoreStateData.items[eventData.id]
    })
    .map(function onMap(entityStoreStateData) {
      return {
        id: eventData.id,
        item: entityStoreStateData.items[eventData.id]
      }
    })
    .take(1)
  })

  return Observable
  .merge(
    gridSelectStream,
    newEntitySelectStream
  )
}