Unknown file extension ".ts" for a TypeScript file

When I try to start my app on Heroku I got the following stack trace.
It is just a basic ts.app like you see with ts-node and nodemon.

I am really interested in what the answer is going to be.

``
2020-05-30T00:03:12.201106+00:00 heroku[web.1]: Starting process with command npm start
2020-05-30T00:03:14.405285+00:00 app[web.1]:
2020-05-30T00:03:14.405303+00:00 app[web.1]: > discordtoornamentmanager@1.0.0 start /app
2020-05-30T00:03:14.405303+00:00 app[web.1]: > ts-node src/App.ts
2020-05-30T00:03:14.405304+00:00 app[web.1]:
2020-05-30T00:03:14.833655+00:00 app[web.1]: (node:23) ExperimentalWarning: The ESM module loader is experimental.
2020-05-30T00:03:14.839311+00:00 app[web.1]: TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /app/src/App.ts
2020-05-30T00:03:14.839312+00:00 app[web.1]: at Loader.defaultGetFormat [as _getFormat] (internal/modules/esm/get_format.js:65:15)
2020-05-30T00:03:14.839314+00:00 app[web.1]: at Loader.getFormat (internal/modules/esm/loader.js:113:42)
2020-05-30T00:03:14.839315+00:00 app[web.1]: at Loader.getModuleJob (internal/modules/esm/loader.js:244:31)
2020-05-30T00:03:14.839315+00:00 app[web.1]: at processTicksAndRejections (internal/process/task_queues.js:97:5)
2020-05-30T00:03:14.839316+00:00 app[web.1]: at Loader.import (internal/modules/esm/loader.js:178:17)
2020-05-30T00:03:14.847801+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2020-05-30T00:03:14.847998+00:00 app[web.1]: npm ERR! errno 1
2020-05-30T00:03:14.848957+00:00 app[web.1]: npm ERR! discordtoornamentmanager@1.0.0 start: ts-node src/App.ts`
2020-05-30T00:03:14.849050+00:00 app[web.1]: npm ERR! Exit status 1
2020-05-30T00:03:14.849172+00:00 app[web.1]: npm ERR!
2020-05-30T00:03:14.849254+00:00 app[web.1]: npm ERR! Failed at the discordtoornamentmanager@1.0.0 start script.
2020-05-30T00:03:14.849337+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2020-05-30T

Remove "type": "module" from package.json

https://github.com/TypeStrong/ts-node/issues/935

https://github.com/TypeStrong/ts-node/issues/1007#issuecomment-1163471306

If you don't want to remove "type": "module" (for example if you're using import statements in your .ts which allows the inference of types from modules), then you can use the following option in tsconfig.json:

{
  "compilerOptions": {
    "esModuleInterop": true,
  }
}

And then you can start the server with the config using ts-node.

Install:

npm install -g ts-node

Run:

ts-node-esm my_server.ts

Stack Overflow Q#62096269, score: 595