Files
camc314 d7713ad4cb fix(parser): classify Unicode line breaks in block comments (#26536)
Block comments containing U+2028 or U+2029 were marked `SingleLineBlock` unless they also contained LF or CR. Switch to the multiline-comment scanner after either Unicode separator so downstream consumers receive the correct comment kind.

This prevents the formatter from dropping parentheses around a return argument with such a leading comment, which could change the returned value to `undefined`.
2026-09-10 15:28:49 +00:00
..

Oxc Parser

High-performance JavaScript and TypeScript parser with comprehensive language support.

Overview

This crate provides a fast, spec-compliant parser for JavaScript and TypeScript that produces a complete Abstract Syntax Tree (AST). It supports all modern language features including JSX, TSX, and the latest ECMAScript proposals.

Key Features

  • Complete language support: JavaScript, TypeScript, JSX, and TSX
  • Latest ECMAScript: All stable ECMAScript features plus stage 3+ proposals
  • High performance: Significantly faster than traditional parsers
  • Error recovery: Continues parsing after errors to provide complete AST
  • Comprehensive AST: Detailed node information with accurate source positions

Architecture

Parser Design

  • Recursive descent: Traditional recursive descent parser architecture
  • Error recovery: Sophisticated error recovery for IDE-friendly parsing
  • Memory efficient: Uses arena allocation for optimal performance
  • Streaming: Processes source text in a single pass

Language Support

  • JavaScript: Full ECMAScript 2024+ support
  • TypeScript: Complete TypeScript syntax including decorators
  • JSX/TSX: React JSX and TypeScript JSX syntax
  • Proposals: Stage 3 decorators and other advancing proposals

AST Structure

The parser produces an AST that closely follows ECMAScript specifications:

  • Accurate positions: Every node has precise source location information
  • Complete information: Preserves all syntactic details including trivia
  • Type-safe: Leverages Rust's type system for correctness
  • Visitor-friendly: Designed for easy traversal and transformation

The parser is designed as the foundation for all other oxc tools, providing the high-quality AST needed for analysis, transformation, and code generation.