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October 17, 2021 17:00
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Add counter for Firestore Collection
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// functions/income/counter.function.js | |
'use strict' | |
const functions = require('firebase-functions') | |
const admin = require('firebase-admin') | |
// Prevent firebase from initializing twice | |
try { admin.initializeApp(functions.config().firebase) } catch (e) {} | |
// My collection is called "incomes" | |
const incomeRef = functions.firestore.document('incomes/{incomeId}') | |
// My counter is allocated in `/counters/incomes`, maybe you wanna follow this structure instead: https://firebase.google.com/docs/firestore/solutions/counters | |
const counterRef = functions.firestore.document('counters/incomes') | |
// These references are not the same as Firestore DocumentReferences | |
// check https://firebase.google.com/docs/reference/functions/functions.firestore.DocumentBuilder | |
// Perform an increment when income is added | |
module.exports.incrementIncomesCounter = incomeRef.onCreate(event => { | |
const counterRef = event.data.ref.firestore.doc('counters/incomes') | |
counterRef.get() | |
.then(documentSnapshot => { | |
const currentCount = documentSnapshot.exists ? documentSnapshot.data().count : 0 | |
counterRef.set({ | |
count: Number(currentCount) + 1 | |
}) | |
.then(() => { | |
console.log('Incomers counter increased!') | |
}) | |
}) | |
}) | |
// Perform an decrement when income is deleted | |
module.exports.decrementIncomesCounter = incomeRef.onDelete(event => { | |
const counterRef = event.data.ref.firestore.doc('counters/incomes') | |
counterRef.get() | |
.then(documentSnapshot => { | |
const currentCount = documentSnapshot.exists ? documentSnapshot.data().count : 0 | |
counterRef.set({ | |
count: Number(currentCount) - 1 | |
}) | |
.then(() => { | |
console.log('Incomers counter decreased!') | |
}) | |
}) | |
}) | |
// Perform a fresh recount(this is expensive) when the counter is deleted (This is optional as well) | |
module.exports.recountIncomesCount = counterRef.onDelete(event => { | |
const incomesRef = event.data.ref.firestore.collection('incomes') | |
return incomesRef.get() | |
.then(querySnapshot => { | |
counterRef.set({ | |
count: querySnapshot.docs.length | |
}) | |
}) | |
}) |
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// functions/index.js | |
/** EXPORT ALL FUNCTIONS | |
* | |
* - Loads all `.function.js` files | |
* - Supports multiple exports from a single `.function.js` file | |
* - It is optimized with `FUNCTION_NAME` env and omiting `node_modules` as well | |
* - Every function from any file must have unique name | |
* - Default export is not supported (`module.exports = ...`), instead use: `module.exports.functionName = ...` | |
* | |
* Based on this thread: | |
* https://github.com/firebase/functions-samples/issues/170 | |
*/ | |
const glob = require('glob') // npm i -S glob | |
const files = glob.sync('./**/*.function.js', { cwd: __dirname, ignore: './node_modules/**' }) | |
files.forEach(file => { | |
const functionModule = require(file) | |
const functionNames = Object.keys(functionModule) | |
functionNames.forEach(functionName => { | |
if (!process.env.FUNCTION_NAME || process.env.FUNCTION_NAME === functionName) { | |
exports[functionName] = functionModule[functionName] | |
} | |
}) | |
}) |
The index.js
works great for me, thanks!
@AntonKL I haven't tested the example function, but I'm using admin.firestore()
to get a firestore reference.
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Cool one! I can't get this one to work at current date, maybe the API has changed?
Keep getting Cannot read property 'firestore' of undefined, so I guess it won't init correctly!