tsconfig.json actually supports trailing commas

[DecimalTurn]

The draft spec was recently edited to include reasons why trailing commas should not be supported. A major reason that was mentioned multiple times in issues/discussion in the VS Code repo is that tsconfig.json doesn't support trailing commas.

However, this last statement is incorrect. tsconfig.json files do support trailing commas according to the schema on schemastore.

Note

Because VS Code automatically uses the tsconfig schema for tsconfig.json file, it won't show a warning for tsconfig.json files with trailing commas.

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "$comment": "Note that this schema uses 'null' in various places. The value of 'null' is UNDOCUMENTED (https://github.com/microsoft/TypeScript/pull/18058)",
  "allowTrailingCommas": true,
  "allOf": [
	...

Hence, considering the following... :

• The official Typescript tsconfig parser supports it (source).
• 2 out of the 3 most popular npm packages used to parse tsconfig files support it:
  • 🟢 https://www.npmjs.com/package/get-tsconfig ✅
  • 🔵 https://www.npmjs.com/package/tsconfck ✅
  • 🟠 https://www.npmjs.com/package/tsconfig ❌ (unmaintained)

... we should should consider removing the mention that tsconfig.json doesn't support trailing commas.

[ell1e]

I still think that JSONC doesn't make much sense without trailing commas by default, given the VS Code UI accepts them and even seems to encourage them for the VS Code config.

However, the official node-jsonc-parser still defaults to disabling them and there's no maintainer response so far. So I guess it's still up in the air, if that's what we want to depend on.

[DecimalTurn]

Considering that .eslintrc.json is now depreciated , I'm not aware of any important actively supported JSONC file that doesn't support trailing commas. This makes me think that the position on trailing commas in this spec needs to change, but I haven't settled on the exact wording yet.