Oxc Docs

Oxc Expert

Official Documentation: https://oxc.rs/docs/guide/introduction.html Learn (Parser Tutorial): https://oxc.rs/docs/learn/parserinrust/intro.html GitHub: https://github.com/oxc-project/oxc Playground: https://playground.oxc.rs

What is Oxc?

Oxc (The JavaScript Oxidation Compiler) is a collection of high-performance JavaScript tools written in Rust. It includes:

• Parser — Fastest JS/TS parser, 3x faster than swc parser
• Linter (Oxlint) — 840+ rules, 50-100x faster than ESLint, ESLint-compatible
• Formatter (Oxfmt) — Prettier-compatible formatter
• Transformer — TS type stripping, JSX, decorators, lowering (ES2026→ES2015)
• Minifier — Dead code elimination, mangling, syntax normalization
• Resolver — 28x faster than webpack/enhanced-resolve

Quick Reference

| Topic | File | |------|------| | Lexer, AST, Parser, Errors, Semantic Analysis tutorial | oxc-parser-tutorial.md | | Parser, Linter, Test Infrastructure, AST Tools architecture | oxc-architecture.md | | ECMAScript Specification, Grammar quirks | oxc-ecmascript.md | | Performance optimization techniques | oxc-performance.md | | Tool usage guide (parser, linter, formatter, transformer, minifier, resolver) | oxc-usage-guide.md |

Compiler Frontend Pipeline

Source Text --> Lexer --> Token --> Parser --> AST

Philosophy

1. Performance is a feature — speed is a product requirement; regressions are bugs
2. One toolchain, shared building blocks — all tools built on shared components for consistency
3. Correctness with clear boundaries — differences from other tools are documented
4. Practical developer experience — sensible defaults, understandable config, stable output

Core Design Principles

1. Allocate less memory — use memory arenas (bumpalo), string inlining (CompactString)
2. Use fewer CPU cycles — SIMD for whitespace, small enum sizes, cache-friendly layouts
3. Zero-cost abstractions — Rust's abstractions compile to efficient machine code
4. Composition over inheritance — no inheritance in Rust; use traits and composition
5. Two-phase design — parse to AST first, then semantic analysis separately

Key Crates

| Crate | Purpose | |-------|---------| | oxc_allocator | Memory arena (bumpalo-based) for AST allocation | | oxc_ast | AST node types and definitions | | oxc_parser | Recursive descent parser | | oxc_semantic | Semantic analysis (scopes, symbols, references) | | oxc_linter | Linting engine (oxlint) | | oxc_diagnostics | Error reporting with miette | | oxc_span | Source span tracking (u32 offsets) | | oxc_formatter | Code formatter (oxfmt) | | oxc_transformer | TS/JSX/decorator/lowering transforms | | oxc_minifier | Dead code elimination, mangling | | oxc_resolver | Module resolver (enhanced-resolve compatible) |

Terminology

| Term | Definition | |------|-----------| | Binding | A value assigned/bound within a scope | | Scope | A block where bindings exist; hierarchical with parent/child | | Scope flags | Metadata about scope (function, top-level, constructor, etc.) | | Symbol | A binding wrapper with references to usage sites; assigned an ID | | Reference | Usage of a symbol; flagged as read, write, or both | | Span | Start/end offset (u32) of a node within source text |

Usage Example

use oxc_allocator::Allocator;
use oxc_parser::Parser;
use oxc_semantic::SemanticBuilder;

let allocator = Allocator::default();
let source_text = "const x = 1;";
let source_type = oxc_span::SourceType::default();

// Phase 1: Parse to AST
let parser_result = Parser::new(&allocator, source_text, source_type).parse();

// Phase 2: Semantic analysis
let semantic_result = SemanticBuilder::new()
    .with_check_syntax_error(true)
    .build(&parser_result.program);

Conformance

• Test262: 100% pass rate on ECMAScript conformance tests
• Babel: 99.62% compatibility with Babel parser tests
• TypeScript: 99.86% compatibility with TypeScript compiler tests

npm Packages

| Package | Tool | |---------|------| | oxc-parser | Parser (Node.js binding) | | oxlint | Linter | | oxc-transform | Transformer (Node.js binding) | | oxc-minify | Minifier (Node.js binding) | | oxc-resolver | Resolver (Node.js binding) | | @oxlint/migrate | ESLint config migration tool | | eslint-plugin-oxlint | Disable overlapping ESLint rules | | unplugin-oxc | Universal plugin for transform/minify | | unplugin-isolated-decl | Isolated declarations plugin | | oxc-webpack-loader | Webpack loader |

References

• ECMAScript Spec
• TypeScript 1.8 Spec
• JSX Spec
• The Rust Performance Book
• Pratt Parsing Tutorial
• V8: Understanding ECMAScript
• V8: Blazingly fast parsing
• JS Syntactic Quirks
• Crafting Interpreters
• Faster than Rust and C++: PERFECT hash table
• Small strings in Rust
• Rust Atomics and Locks
• String Interners in Rust

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: pledgeandgrow
• Source: pledgeandgrow/pledge-skills
• License: MIT

Install and usage instructions live in the source repository linked above.