New user confusion: as soon as you supply a .swcrc file, swc stops recognizing Typescript syntax

[jfirebaugh]

Describe the bug

Hi, just wanted to share my perspective on a point of confusion I encountered as a brand new swc user. Hopefully it's helpful as insight on something that could potentially be improved in the user experience of swc. If not, feel free to close this issue!

I first started using swc without any config file and was happy to find that it could transpile all my .ts files without any issues. Yay!

Then I noticed that the output module format was the same as the input (ES6). I actually need CommonJS output. So, following the documentation I found here, I added an .swcrc file with:

{
  "$schema": "http://json.schemastore.org/swcrc",
  "module": {
    "type": "commonjs"
  }
}

This didn't work. The commands that were formerly working were now producing all kinds of confusing errors. It looked like swc stopped recognizing TypeScript syntax at all!

It took me a while to figure out that as soon as I added an .swcrc file, I needed to start explicitly telling swc that my .ts inputs were in fact TypeScript, by adding "syntax": "typescript" to the .swcrc file.

It seems like swc could have handled this better. In decreasing order of personal preference, here are some suggestions:

• Even without an explicit "syntax": "typescript" in the .swcrc, swc could default to interpreting .ts (and .tsx) files as TypeScript, as it seems to do just fine when there is no .swcrc file.
• If for some reason that's not possible, swc's output in the case where syntax errors are encountered in a .ts file and TypeScript syntax is not enabled could suggest to the user that they add "syntax": "typescript" to the .swcrc file.
• Lastly, the documentation could make it clearer that the default for "syntax" is not exactly "ecmascript", but depends on whether or not an .swcrc file exists or not. (This seems like an inherently confusing behavior though, so I'd recommend avoiding it if possible.)

Input code

No response

Config

No response

Playground link

No response

Expected behavior

See above

Actual behavior

No response

Version

v1.3.61

Additional context

No response