Cannot use mikro-orm-cli in TypeScript with ESM and NodeNext module resolution

[BeiyanYunyi]

Describe the bug

With these configuration, mikro-orm command will not work as expected.

// package.json
"type": "module",
"mikro-orm": {
  "useTsNode": true
}

// tsconfig.json
  "compilerOptions": {
    "target": "ESNext",
    "module": "NodeNext",
    "moduleResolution": "NodeNext"
  }
  "ts-node": { "esm": true }

For reprodution, error stack and more details, see https://github.com/lixiang810/mikro-orm-repro

[B4nan]

You can see working ESM project here: https://stackblitz.com/edit/mikro-orm-esm-repro

The trick to make the CLI work is the ts-node/esm loader, otherwise you can't dynamically load a TS file. I am not aware of any way to achieve this automatically.

edit: huh the repro did not have the script for CLI, so here it is:

"mikro-orm": "NODE_OPTIONS='--loader ts-node/esm --no-warnings' mikro-orm",

Add this to your NPM scripts are use that instead of npx/yarn run the the CLI.

[BeiyanYunyi]

huh the repro did not have the script for CLI

I'm sure that npm exec mikro-orm works without adding it to script section.

You can see working ESM project here: https://stackblitz.com/fork/mikro-orm-esm-repro

It doesn't have @mikro-orm/cli. To make my esm project work is easy, I did it before, but I still can't use the cli.

[B4nan]

I'm sure that npm exec mikro-orm works without adding it to script section.

The reason for NPM script is to have the loader registered.

I see you even found out the trick with loaders yourself. Next time I would appreciate you put such information into the issue description. IMHO this is a wontfix, you already do the right thing to solve it. Just wrap it into NPM script.

[B4nan]

Just to shed a bit more light into this - AFAIK the ts-node-esm works pretty much the same as the proposed workaround here, it spawns new node process with the loader. We can't do this from inside the ORM automatically (at least I am not aware of any way).

I will be definitely experimenting with this more, especially because the new getting started guide I am working on is ESM and also talks about this problem - and I would very much like to not mention it at all and have things working out of box... But I dont think they can at this point.

[B4nan]

FYI open a GH discussion to verify we can't do better:

TypeStrong/ts-node#1880

[B4nan]

I think we could do one thing - we could expose mikro-orm-esm script, which would automatically register the ts-node/esm loader. It sounds a bit confusing as you need it only for TS projects (and it will require ts-node to be installed), but I guess its better than describing this loader env vars and stuff.

[alexojegu]

I am trying ESM, but when I use mikro-orm-esm I only get:

npx -w @tattoo/server mikro-orm-esm schema:create -r
/usr/bin/env: «node --loader ts-node/esm --no-warnings»: The file or directory does not exist
/usr/bin/env: use -[v]S to pass options in shebang lines

When I use a package.json script:

"mikro-orm": "NODE_OPTIONS='--loader ts-node/esm --no-warnings' mikro-orm"

All work as expected:

npm -w @tattoo/server run  mikro-orm schema:create -- -r

> @tattoo/server@0.0.1 mikro-orm
> NODE_OPTIONS='--loader ts-node/esm --no-warnings' mikro-orm

Schema successfully created

[B4nan]

Well, that sounds like npx bug, nothing I can help with. Maybe try moving the workspace argument to different place.

[alexojegu]

After see the CLI code and how you register the ts-node/esm:

mikro-orm/packages/cli/src/esm.ts

Line 1 in 307d3a1

#!/usr/bin/env node --loader ts-node/esm --no-warnings

I have changed in my node_modules/@mikro-orm/cli/esm.js this:

#!/usr/bin/env node --loader ts-node/esm --no-warnings

by this (see the -S):

#!/usr/bin/env -S node --loader ts-node/esm --no-warnings

And all work as expected:

npx -w @tattoo/server mikro-orm-esm schema:create -r
Schema successfully created

[B4nan]

Interesting, PR welcome 👍