--emit option is not emitting files

[Janpot]

Search Terms

emit

Expected Behavior

When you run the command with --emit options, a folder .ts-node is created that contains the transpiled code.

Actual Behavior

No such folder is created

Steps to reproduce the problem

mkdir ts-node-repro
cd ts-node-repro 
npm init --yes
npm add ts-node typescript
npx tsc --init
echo 'console.log("hello")' > index.ts
npx ts-node --emit index.ts 
ls .ts-node

Result:

ls: .ts-node: No such file or directory

Specifications

ts-node v10.4.0
node v16.5.0
compiler v4.4.4

• Operating system and version: MacOs 11.6

Related issue: #1531

[cspotcode]

Looks like files are only written in the compilerHost codepath: https://github.com/TypeStrong/ts-node/blob/main/src/index.ts#L1111

This means that today, emit only works when using compilerHost & not using transpileOnly. Our swc integration falls under the transpileOnly umbrella.
https://typestrong.org/ts-node/docs/options

If someone wants to send us a PR resolving this issue, I can see two solutions:

• a) update the docs to describe this limitation
• b) update both transpileOnly and non-compilerHost codepaths to emit.
  • for this, you may have to do some extra work mapping from rootDir to outDir. I'm not sure.

[cspotcode]

Closing as tracked by other tickets.

There's one about adding a ts-node-emit / ts-node --emit command #1175

Docs already note that --emit requires --compilerHost

[jbriales]

Even though the docs already state that --emit requires --compilerHost, as a beginner I struggled to find why this feature was not working for me.
The reason was that I had set up the config to run with --cws. After reading above, I see why that didn't work.

I'd suggest to improve the docs in this sense:

• State that for --emit to work you cannot be using --transpileOnly (or --cws)
• I'd clarify that the .ts-node folder will appear in the CWD. Otherwise, I confused this with some "global" output folder in the installation folder of ts-node or similar. Specially when I didn't see anything locally, because --cws prevented it :) And I had never run with --emit before.