firebaseでデプロイする際のエラーと対処

エラー

=== Deploying to 'test'...

i  deploying functions, hosting
i  functions: ensuring necessary APIs are enabled...
✔  functions: all necessary APIs are enabled
i  functions: preparing functions directory for uploading...

Error: Error parsing triggers: Cannot find module 'firebase-functions'

Try running "npm install" in your functions directory before deploying.

対処方

この時には

npm install -g firebase-tools

だけでなく

npm install firebase-functions@latest firebase-admin@latest --save
npm install -g firebase-tools

にし、もう一度デプロイ