fluorine-orchestra/src/util/combineStores.js

A data orchestration layer for Fluorine

/* eslint prefer-rest-params: 0 */

import invariant from 'invariant'
import { Observable } from 'rxjs'
import isObservable from 'fluorine-lib/lib/util/isObservable'

export default function combineStores(stores) {
  invariant(
    typeof stores === 'object',
    'combineStores: `stores` is expected to be an object containing Observables.')

  const keys = Object.keys(stores)

  return Observable.combineLatest(
    ...keys.map(key => {
      const store = stores[key]

      invariant(
        isObservable(store),
        'combineStores: `stores` is expected to contain Observables only.')

      return store
    }),
    (...args) => {
      const state = {}

      args.forEach((arg, index) => {
        const key = keys[index]
        state[key] = arg
      })

      return state
    }
  )
}