Heroku + Node: Cannot find module error

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My Node app is running fine locally, but has run into an error when deploying to Heroku. The app uses Sequelize in a /models folder, which contains index.js, Company.js and Users.js. Locally, I am able to import the models using the following code in /models/index.js:

// load models
var models = [
  'Company',
  'User'
];
models.forEach(function(model) {
  module.exports[model] = sequelize.import(__dirname + '/' + model);
});

This works fine, however, when I deploy to Heroku the app crashes with the following error:

Error: Cannot find module '/app/models/Company'
   at Function.Module._resolveFilename (module.js:338:15)
   at Function.Module._load (module.js:280:25)
   at Module.require (module.js:364:17)
   at require (module.js:380:17)
   at module.exports.Sequelize.import (/app/node_modules/sequelize/lib/sequelize.js:219:24)
   at module.exports.sequelize (/app/models/index.js:60:43)
   at Array.forEach (native)
   at Object.<anonymous> (/app/models/index.js:59:8)
   at Module._compile (module.js:456:26)
   at Object.Module._extensions..js (module.js:474:10)
Process exited with status 8

Initially I thought it was due to case sensitivity (local mac vs heroku linux), but I moved the file, made a git commit, and then moved back and committed again to ensure Company.js is capitalized in the git repository. This didn’t solve the problem and I’m not sure what the issue could be.

Answer

The problem was due to case sensitivity and file naming. Mac OS X is case insensitive (but aware) whereas Heroku is based on Linux and is case sensitive. By running heroku run bash from my terminal, I was able to see how the /models folder appeared on Heroku’s file system. The solution was to rename User.js and Company.js on my local system to new temporary files, commit the changes to git, then rename back to User.js and Company.js being mindful of the capitalized first letter and then committing the changes again via git. Previously I had tried to rename the files directly from user.js to User.js and company.js to Company.js but the git commit and case-sensitive file name changes did not reflect on Heroku.



Source: stackoverflow