There seems to be an issue with the contructor of FieldPath of firestore-admin. This issue only occurs in Emulator mode, not in cloud functions that are live on Firebase/GCP.
- Checkout project
- Add your firebase project id in .firebaserc
- switch to functions folder and run
npm i && npm run build && firebase emulators:start - add a new document to firestore in a collection named
test - See error appearing in log output of the emulator.
Error that appears and breaks function:
⚠ functions: TypeError: admin.firestore.FieldPath is not a constructor
at /###/functions/lib/index.js:11:18
at cloudFunction (/###/functions/node_modules/firebase-functions/lib/cloud-functions.js:78:23)
at /usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:516:16
at runFunction (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:504:15)
at runBackground (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:515:11)
at processBackground (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:499:11)
at /usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:690:27
at Layer.handle [as handle_request] (/usr/local/lib/node_modules/firebase-tools/node_modules/express/lib/router/layer.js:95:5)
at next (/usr/local/lib/node_modules/firebase-tools/node_modules/express/lib/router/route.js:137:13)
at next (/usr/local/lib/node_modules/firebase-tools/node_modules/express/lib/router/route.js:131:14)
You can downgrade firebase-admin to version 10. This fixes the issue:
Run npm i firebase-admin@10 in functions folder followed by step 3 onward (see above)