Firebase hooks!

useFirestore.js

import { useState } from "react"
import Firebase from "firebase"

const db = Firebase.firestore()

export const useCollection = options => {
  const [documents, setDocuments] = useState(null)

  if (!options.path) {
    throw new Error("A path must be specified")
  }

  let ref = db.collection(options.path)
  let add = ref.add

  if (options.query) {
    ref = ref.where(query)
  }

  ref.onSnapshot({
    next: snapshot => {
      console.log(snapshot)
      setDocuments(snapshot.docs())
    },
    error: error => console.error(error)
  })

  return { documents, add }
}

export const useDocument = options => {
  const [data, setData] = useState(null)

  if (!options.path) {
    throw new Error("A path must be specified")
  }

  const ref = db.doc(options.path)
  const { set, update, delete: remove } = ref
  ref.onSnapshot({
    next: snapshot => setData(snapshot.data()),
    error: error => console.error(error)
  })

  return { data, set, update, remove }
}