Using a Firestore Cloud Functions - node.js

Question

I have this problem. In my code depends of choosen project name I want to retrieve a document from another collection. I am use
exports.updateUser = functions.firestore
.document('Users/{userId}')
.onUpdate((change, context) => {
const newValue = change.after.data().currentProject;
console.log("Project changed to - " + newValue);
const previousValue = change.before.data().currentProject;
console.log("from - " + previousValue);
// ### FROM HERE DOES NOT WORK ###
const projectId = firestore.collection('Projects')
.where('name', '==', newValue).get()
.then(doc => {
console.log(doc.data().id);
return doc.data().id;
});
});
And I get an error
ReferenceError: firestore is not defined
at exports.updateUser.functions.firestore.document.onUpdate (/user_code/index.js:25:14)
So maybe I need another dependencies ?
My package.json is
{
"name": "functions",
"description": "Cloud Functions for Firebase",
"scripts": {
"lint": "eslint .",
"serve": "firebase serve --only functions",
"shell": "firebase functions:shell",
"start": "npm run shell",
"deploy": "firebase deploy --only functions",
"logs": "firebase functions:log"
},
"dependencies": {
"firebase-admin": "~5.12.0",
"firebase-functions": "^1.0.1"
},
"devDependencies": {
"eslint": "^4.12.0",
"eslint-plugin-promise": "^3.6.0"
},
"private": true
}
What I am missing? Please give a hint

Answer 1

You will need to use the Firebase Admin SDK to access Firestore collections that are outside of the scope that your function was triggered on. Typically this will look something like:
admin.firestore().collection('Projects')...