Whenever I run node oauth module I get error like
app.oauth.grant is not a function
I had the same problem yesterday. I switched my dependencies to a lower version of the libraries and things worked. What I ended up with:
"body-parser": "^1.15.2",
"express": "^4.14.0",
"oauth2-server": "^2.4.1",
"request": "^2.83.0"