# tree_sitter_typescript::language_tsx in Rust — the right way to wire it up

How to use `tree_sitter_typescript::language_tsx()` from Rust without crashing on JSX-heavy files. Crate version compatibility, parser init, and how Aura uses it.

The `tree-sitter-typescript` crate exposes two grammars: `language_typescript()` for plain `.ts` files, and **`tree_sitter_typescript::language_tsx()`** for `.tsx` files containing JSX. Pick the wrong one and the parser silently truncates every JSX subtree to `ERROR` nodes — which is exactly what Aura's AST-diff engine handled wrong in v0.4 and now treats as a hard precondition.

## Cargo.toml

```
[dependencies]
tree-sitter        = "0.22"
tree-sitter-typescript = "0.21"
```

## Minimal parser setup

```
use tree_sitter::Parser;

fn parse_tsx(source: &str) -> tree_sitter::Tree {
    let mut parser = Parser::new();
    parser
        .set_language(&tree_sitter_typescript::language_tsx())
        .expect("load tsx grammar");
    parser.parse(source, None).expect("parse")
}
```

## Pitfalls Aura hit (so you don't have to)

- **One parser, one grammar.** Re-using the same `Parser` across `.ts` and `.tsx` files without calling `set_language` again leaves you parsing TSX with the TypeScript grammar — most JSX becomes `ERROR` nodes and your diff is meaningless.
- **Version skew.** `tree-sitter` 0.22 ABI requires a `tree-sitter-typescript` built against the same major. Mixing 0.20 + 0.22 compiles fine, then segfaults at runtime when the parser walks a sufficiently deep tree.
- **UTF-16 source.** `parse` assumes UTF-8. If you're feeding it bytes from VS Code over LSP, decode first or use `parse_with_options`.
- **Cancellation timeouts.** Set `parser.set_timeout_micros(…)` for adversarial inputs — a hand-crafted JSX file can blow up the parser for > 30s otherwise.

## How Aura uses it

Aura's AST-diff engine runs `language_tsx()` against every `.tsx` commit, extracts named function nodes, and hashes their structural skeleton (rename-proof identity). When Claude rewrites `<UserCard>` from a class component to a functional one, Aura sees one node updated, not 200 lines deleted + 180 added — and the intent log says exactly that.

## Reference

The grammar source lives at [tree-sitter/tree-sitter-typescript](https://github.com/tree-sitter/tree-sitter-typescript). The Aura wrapper that picks the right grammar per file extension is in `aura-stackgraph/src/lang/typescript.rs` (Apache 2.0).