Heroku NodeJS cannot find module

Question

I have an application that's running fine locally, but cannot run when deployed. The message is

Error: Cannot find module 'jsonwebtoken'

even though I have it in "dependencies" in my package.json (not devdependency)

I tried "heroku run bash" and verified that jsonwebtoken exists in the node_modules folder.
Finally I tried "heroku local web" and it works fine. But for some reason it never works when deployed.

This is the start of the file that needs jsonwebtoken

var mongoose = require('mongoose');
var crypto = require('crypto');
console.log('check1');
var jwt = require('jsonwebtoken');
console.log('check2');

It gets to "check1" but not "check2"

This is my package.json

{
  "name": "loc8r",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "engines": {
    "node": "~0.10.13",
    "npm": "~1.3.2"
  },
  "dependencies": {
    "body-parser": "~1.8.1",
    "cookie-parser": "~1.3.3",
    "debug": "^2.0.0",
    "dotenv": "^4.0.0",
    "express": "~4.9.0",
    "express-jwt": "^5.3.0",
    "jade": "~1.6.0",
    "jsonwebtoken": "^8.1.0",
    "mongoose": "^4.13.5",
    "morgan": "~1.3.0",
    "passport": "^0.4.0",
    "passport-local": "^1.0.0",
    "request": "~2.51.0",
    "serve-favicon": "~2.1.3",
    "uglify-js": "~2.4.15"
  },
  "description": "myapp",
  "main": "app.js",
  "devDependencies": {},
  "keywords": [],
  "author": "",
  "license": "ISC"
}

Can someone please help me figure out what's going on?

Answer 1

The node version you are using on Heroku is too old judging from the package.json of jsonwebtoken. I would suggest upgrading to the latest version.

I'm pretty sure it works locally for you because you are running a newer version than 0.10.X on your own computer.