Defaulting to `ts-node` is confusing when using ESM loaders

• Versions: node@v16.15.1, darwin@21.6.0
• nodemon -v: 2.0.20
• Operating system/terminal environment (powershell, gitshell, etc): macOS, Terminal.app, zsh
• Using Docker? What image: no
• Command you ran: NODE_OPTIONS='--loader @esbuild-kit/esm-loader' nodemon src/server.ts

Expected behaviour

I was expecting @esbuild-kit/esm-loader being used to load my TypeScript files, as that is the case when I run NODE_OPTIONS='--loader @esbuild-kit/esm-loader' node src/server.ts (same command but with node instead of nodemon).

Actual behaviour

It uses ts-node in order to transpile the TypeScript files.

I only noticed this because source maps wasn’t working properly, and upon investigating that I realised that nodemon had actually used ts-node to transpile the typescript files.

Steps to reproduce

1. Create the following package.json file

   {
     "type": "module",
     "dependencies": {
       "@esbuild-kit/esm-loader": "^2.5.0",
       "nodemon": "^2.0.20"
     }
   }
   

2. Run npm install
3. Create the following index.ts file:

   const test = (foo: string) => { throw new Error(foo) }
   
   test('foo')
   

4. Run NODE_OPTIONS='--loader @esbuild-kit/esm-loader' node index.ts
5. Observe nice stack trace
6. Run NODE_OPTIONS='--loader @esbuild-kit/esm-loader' nodemon index.ts

7. failed to start process, “ts-node” exec not found

[remy]

I genuinely don’t care about TS support, but it’s been in nodemon for too long that removing it would probably break expectations.

I think checking the --loader is the best (soft) approach that could solve this issue.

[LinusU]

friendly ping @remy