Node.JS app crash on startup after second deployment on Heroku

Question

I did git push heroku master for the second time. But I got the error cannot find module .... For the first time, I succeeded.

How can I fix this? Thanks.

    2021-01-03T16:03:35.301824+00:00 app[web.1]: internal/modules/cjs/loader.js:818
    2021-01-03T16:03:35.301837+00:00 app[web.1]: throw err;
    2021-01-03T16:03:35.301837+00:00 app[web.1]: ^
    2021-01-03T16:03:35.301837+00:00 app[web.1]:
    2021-01-03T16:03:35.301838+00:00 app[web.1]: Error: Cannot find module './stringToParts'
    2021-01-03T16:03:35.301838+00:00 app[web.1]: Require stack:
    2021-01-03T16:03:35.301839+00:00 app[web.1]: - /app/node_modules/mpath/lib/index.js
    2021-01-03T16:03:35.301839+00:00 app[web.1]: - /app/node_modules/mpath/index.js
    2021-01-03T16:03:35.301839+00:00 app[web.1]: - /app/node_modules/mongoose/lib/utils.js
    2021-01-03T16:03:35.301840+00:00 app[web.1]: - /app/node_modules/mongoose/lib/statemachine.js
    2021-01-03T16:03:35.301841+00:00 app[web.1]: - /app/node_modules/mongoose/lib/internal.js
    2021-01-03T16:03:35.301841+00:00 app[web.1]: - /app/node_modules/mongoose/lib/document.js
    2021-01-03T16:03:35.301841+00:00 app[web.1]: - /app/node_modules/mongoose/lib/index.js
    2021-01-03T16:03:35.301842+00:00 app[web.1]: - /app/node_modules/mongoose/index.js
    2021-01-03T16:03:35.301842+00:00 app[web.1]: - /app/models/user.js
    2021-01-03T16:03:35.301843+00:00 app[web.1]: - /app/controllers/usersController.js
    2021-01-03T16:03:35.301843+00:00 app[web.1]: - /app/routes/userRoutes.js
    2021-01-03T16:03:35.301844+00:00 app[web.1]: - /app/routes/index.js
    2021-01-03T16:03:35.301845+00:00 app[web.1]: - /app/main.js
    2021-01-03T16:03:35.301845+00:00 app[web.1]: at Function.Module._resolveFilename (internal/modules/cjs/loader.js:815:15)
    2021-01-03T16:03:35.301846+00:00 app[web.1]: at Function.Module._load (internal/modules/cjs/loader.js:667:27)
    2021-01-03T16:03:35.301846+00:00 app[web.1]: at Module.require (internal/modules/cjs/loader.js:887:19)
    2021-01-03T16:03:35.301847+00:00 app[web.1]: at require (internal/modules/cjs/helpers.js:74:18)
    2021-01-03T16:03:35.301847+00:00 app[web.1]: at Object.<anonymous> (/app/node_modules/mpath/lib/index.js:1:21)
    2021-01-03T16:03:35.301848+00:00 app[web.1]: at Module._compile (internal/modules/cjs/loader.js:999:30)
    2021-01-03T16:03:35.301848+00:00 app[web.1]: at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
    2021-01-03T16:03:35.301849+00:00 app[web.1]: at Module.load (internal/modules/cjs/loader.js:863:32)
    2021-01-03T16:03:35.301849+00:00 app[web.1]: at Function.Module._load (internal/modules/cjs/loader.js:708:14)
    2021-01-03T16:03:35.301849+00:00 app[web.1]: at Module.require (internal/modules/cjs/loader.js:887:19) {
    2021-01-03T16:03:35.301850+00:00 app[web.1]: code: 'MODULE_NOT_FOUND',
    2021-01-03T16:03:35.301850+00:00 app[web.1]: requireStack: [
    2021-01-03T16:03:35.301851+00:00 app[web.1]: '/app/node_modules/mpath/lib/index.js',
    2021-01-03T16:03:35.301851+00:00 app[web.1]: '/app/node_modules/mpath/index.js',
    2021-01-03T16:03:35.301851+00:00 app[web.1]: '/app/node_modules/mongoose/lib/utils.js',
    2021-01-03T16:03:35.301852+00:00 app[web.1]: '/app/node_modules/mongoose/lib/statemachine.js',
    2021-01-03T16:03:35.301852+00:00 app[web.1]: '/app/node_modules/mongoose/lib/internal.js',
    2021-01-03T16:03:35.301852+00:00 app[web.1]: '/app/node_modules/mongoose/lib/document.js',
    2021-01-03T16:03:35.301853+00:00 app[web.1]: '/app/node_modules/mongoose/lib/index.js',
    2021-01-03T16:03:35.301853+00:00 app[web.1]: '/app/node_modules/mongoose/index.js',
    2021-01-03T16:03:35.301853+00:00 app[web.1]: '/app/models/user.js',
    2021-01-03T16:03:35.301854+00:00 app[web.1]: '/app/controllers/usersController.js',
    2021-01-03T16:03:35.301854+00:00 app[web.1]: '/app/routes/userRoutes.js',
    2021-01-03T16:03:35.301855+00:00 app[web.1]: '/app/routes/index.js',
    2021-01-03T16:03:35.301855+00:00 app[web.1]: '/app/main.js'
    2021-01-03T16:03:35.301855+00:00 app[web.1]: ]
    2021-01-03T16:03:35.301856+00:00 app[web.1]: }
    2021-01-03T16:03:35.394395+00:00 heroku[web.1]: Process exited with status 1
    2021-01-03T16:03:35.475189+00:00 heroku[web.1]: State changed from starting to crashed
    2021-01-03T16:03:35.479175+00:00 heroku[web.1]: State changed from crashed to starting
    2021-01-03T16:03:39.720428+00:00 heroku[web.1]: Starting process with command `node main.js`

Answer 1

Are you exporting the data in './stringToParts' correctly?

When you require a module like './stringToParts', it must be exported. Check if you have something like this at the end of your './stringToParts' file:

module.exports = function;