feat(parser/napi): add flexbuffer to AST transfer (2x speedup)

[HerringtonDarkholme]

Hi! I have created a proof of concept of improving using oxc in JavaScript. The method is not polished but it provides valuable insights for future direction!

Feel free to close~ It is for reference only :)

Context

This is a proof of concept implementation of passing binary AST to JavaScript. JavaScript can selectively read flexbuffers-based AST nodes on demand to avoid the deserialization toll. More context here.

Changes

• Add a parseSyncBuffer napi method to return a binary AST from Rust to JavaScript. The AST is in flexbuffer format.
• Add a test_buffer.js to test usage of flexbuffers in JavaScript. It is in cjs format because flexbuffers does not support ESM :/

Result

Some preliminary results, for reference only.

~ node test_buffer.js
testJSON: 4.043s
testBuffer: 2.395s

Buffer based API is 100% faster than JSON.

Future Ideas

• Flexbuffers itself is slow. A better binary protocol is desired!
• Using binary reader to traverse AST is undesirable. A proxy-based API to emulate object behavior will be nice.