[feature] supports multiple languages in a rule

[pd4d10]

⭐ Suggestion

supports multiple languages in a rule, for example:

- id: xxx
- languages: [ts, tsx]

💻 Use Cases

There are many common lint cases in ts and tsx. It would be great to config them in one rule, to avoid copy and paste.

[HerringtonDarkholme]

I'm suspecting if using multiple languages in a rule is the real issue here.

JavaScript and TypeScript looks like the same, but they just happened to be similar. Their underlying parsers will produce different ASTs for the same code input.

For example:

(a) => f(a)

Will produce different syntax trees. #1087

Having two similar but different languages in the same rule will confuse users for parsing discrepancies.

Instead, the issue here should be rephrased to

"both JS/TS should be parsed with one language and handled together"

Using language globs is probably the better approach here.
https://ast-grep.github.io/reference/sgconfig.html#languageglobs

Example sgconfig.yml

ruleDirs:
  - rules
languageGlobs:
  TypeScript: ["*.js"]

[HerringtonDarkholme]

Closing as stated above, the more appropriate mental model will be using a superset language to parse subset language via languageGlobs.