feat(napi/parser): add AST walker

[overlookmotel]

Add an AST visitor to oxc-parser.

import { parseSync, Visitor } from 'oxc-parser';

const { program } = parseSync('test.js', 'let x = { y: z };');

const idents = [];
const visitor = new Visitor({
  Identifier(node) {
    idents.push(node.name);
  }
});

visitor.visit(program);

// Logs [ 'x', 'y', 'z' ]
console.log(idents);

Primarily we need a visitor for Oxlint plugins, but it's easier to develop and test in oxc-parser, so I thought I'd add it there first. Oxlint build process will copy the generated files for tree-walking from napi/parser dir, as it does with other files.

Notes:

• The walk.mjs file is large, so it's lazy-loaded only when user first constructs a Visitor. Adding Visitor to the package will not affect start-up time where user only uses parseSync etc.
• TS type definition for Visitor and the visitor object it takes are provided.
• Visitor supports enter and exit visitors e.g. Program and Program:exit.
• src-js/visit/visitor.mjs is copied from apps/oxlint with only minor modifications, and conversion from TS to JS. It'd be better if we only had this impl in one place, but that would require converting oxc-parser to TS and building with TSDown, like oxlint is. Leaving that for later - Convert oxc-parser to TypeScript #13935.

[overlookmotel]

• feat(linter/plugins): add defineRule API #13945
• feat(linter/plugins): add createOnce API #13944
• feat(linter/plugins): ESTree-compatible AST for JS plugins #13942
• feat(napi/parser): add deserializeProgramOnly deserializer function #13940
• feat(napi/parser): add AST walker #13930 👈 (View in Graphite)
• feat(napi/parser): export visitor keys #13927
• fix(napi/parser): raw transfer preserveParens option apply to TSParenthesizedType #13964
• main

---

How to use the Graphite Merge Queue

Add either label to this PR to merge it via the merge queue:

• 0-merge - adds this PR to the back of the merge queue
• hotfix - for urgent hot fixes, skip the queue and merge this PR next

You must have a Graphite account in order to use the merge queue. Sign up using this link.

An organization admin has enabled the Graphite Merge Queue in this repository.

Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.

This stack of pull requests is managed by Graphite. Learn more about stacking.

[overlookmotel]

Merge activity

• Sep 22, 11:08 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Sep 22, 11:08 AM UTC: overlookmotel added this pull request to the Graphite merge queue.
• Sep 22, 11:14 AM UTC: Merged by the Graphite merge queue.