This gist contains the source code in my video series about Realtime Database triggers. You can watch the three parts here:
index.ts contains the Cloud Functions code, and dialog.ts contains the script to run
locally that simulates the addition of messages to the chat room.
| import * as admin from 'firebase-admin' | |
| const serviceAccount = require('../service-account.json') | |
| admin.initializeApp({ | |
| credential: admin.credential.cert(serviceAccount), | |
| databaseURL: `https://${serviceAccount.project_id}.firebaseio.com` | |
| }) | |
| ;(async () => { | |
| await chat('pizzachat', 'Fear', "What the heck is that?!") | |
| await chat('pizzachat', 'Joy', "Who puts broccoli on pizza?!") | |
| await chat('pizzachat', 'Disgust', "That's it. I'm done.") | |
| await chat('pizzachat', 'Anger', "Congratulations, San Francisco! You've ruined pizza!") | |
| process.exit(0) | |
| })() | |
| .catch(err => { console.error(err) }) | |
| async function chat(room: string, name: string, text: string) { | |
| const messagesRef = admin.database().ref('rooms').child(room).child('messages') | |
| await messagesRef.push({ name, text }) | |
| console.log(`${name}: ${text}`) | |
| await sleep(1500) | |
| } | |
| function sleep(ms: number) { | |
| return new Promise(resolve => setTimeout(resolve, ms)); | |
| } |
| import * as functions from 'firebase-functions' | |
| export const onMessageCreate = functions.database | |
| .ref('/rooms/{roomId}/messages/{messageId}') | |
| .onCreate(async (snapshot, context) => { | |
| const roomId = context.params.roomId | |
| const messageId = context.params.messageId | |
| console.log(`New message ${messageId} in room ${roomId}`) | |
| const messageData = snapshot.val() | |
| const text = addPizzazz(messageData.text) | |
| await snapshot.ref.update({ text: text }) | |
| const countRef = snapshot.ref.parent.parent.child('messageCount') | |
| return countRef.transaction(count => { | |
| return count + 1 | |
| }) | |
| }) | |
| export const onMessageDelete = functions.database | |
| .ref('/rooms/{roomId}/messages/{messageId}') | |
| .onDelete(async (snapshot, context) => { | |
| const countRef = snapshot.ref.parent.parent.child('messageCount') | |
| return countRef.transaction(count => { | |
| return count - 1 | |
| }) | |
| }) | |
| function addPizzazz(text: string): string { | |
| return text.replace(/\bpizza\b/g, '🍕') | |
| } | |
| export const onMessageUpdate = functions.database | |
| .ref('/rooms/{roomId}/messages/{messageId}') | |
| .onUpdate((change, context) => { | |
| const before = change.before.val() | |
| const after = change.after.val() | |
| if (before.text === after.text) { | |
| console.log("Text didn't change") | |
| return null | |
| } | |
| const text = addPizzazz(after.text) | |
| const timeEdited = Date.now() | |
| return change.after.ref.update({ text, timeEdited }) | |
| }) |
Hello,
I was following your instructions in the youtube video. But when using change.after.val() - I am getting error: - Object is possibly 'undefined'.ts(2532) (parameter) change: functions.Change<functions.database.DataSnapshot>
Could you please look into it and let me know what was the issue.
Thanks
Shaun