Error: Cannot find module './drivers' with mongoose only on the server

Question

mongoose works fine on the computer

but on the server I get this error:

Error: Cannot find module './drivers'
    at Function.Module._resolveFilename (module.js:336:15)
    at Function.Module._load (module.js:278:25)
    at Function.<anonymous> (/usr/local/lib/node_modules/pm2/node_modules/pmx/lib/transaction.js:59:21)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (/var/www/html/WTV.com/node_modules/mongoose/lib/schema.js:5:16)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)

Answer 1

OK! I took me a while but I found the solution

1. in commandline write: heroku config:set NODE_MODULES_CACHE=false --app
2. make some change and push the project
3. in commandline write: heroku config:set NODE_MODULES_CACHE=true --app

Good luck :)

Answer 2

I recently ran into a similar issue. I am using the MEAN stack with mongoose as my ODM and hosting on Heroku:

Error: Cannot find module './drivers'
at Function.Module._resolveFilename (module.js:326:15)
at Function.Module._load (module.js:277:25)
at Module.require (module.js:354:17)
at require (internal/module.js:12:17)
at Object.<anonymous> (/app/node_modules/mongoose/lib/schema.js:5:16)
at Module._compile (module.js:410:26)
at Object.Module._extensions..js (module.js:417:10)
at Module.load (module.js:344:32)
at Module.require (module.js:354:17)
at Function.Module._load (module.js:301:12)
at require (internal/module.js:12:17)
Process exited with status 1
State changed from starting to crashed

In addition to setting NODE_MODULES_CACHE=false as stated here (under section Cache Behavior), I had to remove my node_modules directory from the git repo (also recommended in the Heroku docs). See this thread on how to remove a directory from git.

Also, adding "node_modules" directory to your .gitignore file is a good idea. NOTE: This does not remove the files from git, you still have to remove any previously committed files or directories that you want ignored.

Answer 3

I simply ran heroku run bash in the cloned directory and typed in rm -rf node_modules and ran npm install from there. Simply ran the server through heroku run bash and worked fine! Hopefully this will work for you. Ensure to have node_modules in your .gitignore file.