Heroku SyntaxError: Unexpected token 'export'

Question

I am developing a node.js / express web app. When I run in my localhost environment. Everything works like a charm. But when I deployed to Heroku, I get the following error:

2020-11-04T19:16:15.678297+00:00 app[web.1]: SyntaxError: Unexpected token 'export'
2020-11-04T19:16:15.678298+00:00 app[web.1]: at wrapSafe (internal/modules/cjs/loader.js:979:16)
2020-11-04T19:16:15.678299+00:00 app[web.1]: at Module._compile (internal/modules/cjs/loader.js:1027:27)
2020-11-04T19:16:15.678299+00:00 app[web.1]: at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
2020-11-04T19:16:15.678299+00:00 app[web.1]: at Module.load (internal/modules/cjs/loader.js:928:32)
2020-11-04T19:16:15.678300+00:00 app[web.1]: at Function.Module._load (internal/modules/cjs/loader.js:769:14)
2020-11-04T19:16:15.678300+00:00 app[web.1]: at Module.require (internal/modules/cjs/loader.js:952:19)
2020-11-04T19:16:15.678301+00:00 app[web.1]: at require (internal/modules/cjs/helpers.js:88:18)
2020-11-04T19:16:15.678301+00:00 app[web.1]: at Object.<anonymous> (/app/twilio/handler.js:3:22)
2020-11-04T19:16:15.678301+00:00 app[web.1]: at Module._compile (internal/modules/cjs/loader.js:1063:30)
2020-11-04T19:16:15.678302+00:00 app[web.1]: at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
2020-11-04T19:16:15.682211+00:00 app[web.1]: error: Forever detected script exited with code: 1
2020-11-04T19:16:15.886448+00:00 app[web.1]: error: Script restart attempt #83
2020-11-04T19:16:16.263688+00:00 app[web.1]: /app/server/utilities.js:3
2020-11-04T19:16:16.263698+00:00 app[web.1]: export function ExpressErrorModel(title, req, error_object, user) {
2020-11-04T19:16:16.263699+00:00 app[web.1]: ^^^^^^

The file that it is referring to has the following module:

const CryptoJS = require("crypto-js");

export function ExpressErrorModel(title, req, error_object, user) {
  let error = {
    error_title: title,
    error_request: req.headers,
    error_object: error_object,
    error_user: user,
    timestamp: new Date(Date.now())
  };
  return error;
}

I am deploying to Heroku with the following engines:

  "engines": {
    "node": "14.x",
    "npm": "6.x"
  },

Have any of you encountered this issue? It works fine on my localhost, but fails on Heroku deploy.

Answer 1

You are mixing CommonJS module syntax ( require ) and ES6 module syntax ( export ).

A module can only use one of these.

Your instance of Node.js is using the CJS loader, so change your module to export in the CJS style:

module.exports = { ExpressErrorModel };