Firebase Cloud functions basic examples

firebase.functions.index.js

const functions = require('firebase-functions');
const admin = require('firebase-admin')
admin.initializeApp(functions.config().firebase)

exports.helloWorld = functions.https.onRequest((request, response) => {
  response.send("Hello Minjun!");
});

// Both of below lines return firestore database object
// admin.firestore() in cloud function
// db = getFirestore() in action creator
const createNotification = (notification) => {
  return admin.firestore().collection('notifications').add(notification)
    .then(doc => {
      console.log('notification added', doc)
    })
}

// function trigger for new project
exports.projectCreated = functions.firestore
  .document('projects/{projectId}')
  .onCreate(doc => {
    const project = doc.data()
    const notification = {
      content: "New Project Created",
      user: project.firstName + ' ' + project.lastName,
      time: admin.firestore.FieldValue.serverTimestamp()
    }
    return createNotification(notification)
  })

// function trigger for new user
exports.userJoined = functions.auth.user()
  .onCreate(user => {
    return admin.firestore().collection('users').doc(user.uid).get()
      .then(doc => {
        const newUser = doc.data()
        const notification = {
          content: "New User Joined",
          user: newUser.firstName + ' ' + newUser.lastName,
          time: admin.firestore.FieldValue.serverTimestamp()
        }
        return createNotification(notification)
      })
  })

// all "return" statement can be ommitted (will show warning though)