Just as a reference:
This makes tools like jsonlint (linting *.json in my project) and visual studio intellisense unhappy. :-(

Does not work with .eslintrc.json files (and maybe many other files, which aren't support jsonc).

#15946

Please revert.

Absolutely breaksjest if you have trailing commas enabled in prettier and import your tsconfig.json in your jest config. The tsconfig can no longer be parsed because of that. I guess a temporary solution would be to ignore formatting the tsconfig.

@fisker @sosukesuzuki

This breaks many JSONs. Changing the parser inference for JSON files from json to jsonc and adding trailing commas to jsonc files breaks with JSON specs that doesn't support trailing commas neither comments. Then is an error parsing json with ´jsonc` parser.

Please rollback to parse JSON with json and later discus about add or remove trailing commas in jsonc parser.

And in the other hands this is not a fix, it's a major change. It's broken all my pipelines.