If you have installed Fontawesome Pro, check ~/.npmrc
.
@fortawesome:registry=https://npm.fontawesome.com/
//npm.fontawesome.com/:_authToken=XXX
Goto your firebase project directory, and copy the content of ~/.npmrc
to functions/.npmrc
.
cd functionscat ~/.npmrc > .npmrc
Run deployment.
firebase deploy
or
firebase deploy --only functions:FUNCTION_NAME
References: