[MrManatee]

For "similar to tree-sitter but js-only", Lezer might be an even closer match:

https://lezer.codemirror.net/

I have used both Ohm and Lezer - for different use cases - and have been happy with both.

If you want a parser that makes it possible for code editors to provide syntax highlighting, code folding, and other such features, Tree-sitter and Lezer work great for that use case. They are incremental, so it's possible to parse the file every time a new character is added. Also, for the editor use case it is essential that they can produce some kind of parse tree even if there are syntax errors.

I wouldn't try to build a syntax highlighter on top of Ohm. Ohm is, as the title says, meant for building parsers, interpreters, compilers, etc. And for those use cases, I think Ohm is easier to build upon than Lezer is.

[usernamesp]

What makes Ohm better for building parsers and compilers?

[MrManatee]

This is more of an interpreter than a compiler, but if you look at the "Arithmetic example with semantics" [1] linked on Ohm's GitHub page, you can see how Ohm can be simultaneously used for both (1) defining a language for arithmetic expressions and (2) defining how those expressions should be evaluated. I don't think Lezer even tries to help with something like this.

[1] https://jsfiddle.net/pdubroy/15k63qae/