Oxc Semantic

Comprehensive semantic analysis for JavaScript and TypeScript programs.

Overview

This crate performs semantic analysis on JavaScript and TypeScript ASTs, building symbol tables, scope trees, and control flow graphs. It provides the foundation for advanced static analysis, linting, and transformation tools.

Key Features

Symbol resolution: Build complete symbol tables with binding information
Scope analysis: Construct scope trees following ECMAScript scoping rules
Reference tracking: Track all variable references and their relationships
Control flow: Optional control flow graph construction
JSDoc parsing: Extract and parse JSDoc comments
Module analysis: Analyze import/export relationships

Architecture

Semantic Analysis Pipeline

AST Traversal: Visit all nodes to collect declarations
Scope Building: Construct scope tree following language rules
Symbol Resolution: Create symbol table with binding information
Reference Analysis: Track all identifier references
Control Flow: Optionally build control flow graphs
JSDoc Processing: Parse and attach documentation

Key Data Structures

Symbol Table

Symbols: All declared identifiers (variables, functions, classes, etc.)
References: All uses of identifiers
Bindings: Association between names and symbols in scopes

Scope Tree

Scope hierarchy: Nested scopes following language semantics
Binding resolution: How identifiers resolve to declarations
Closure analysis: Capture and usage patterns

Control Flow Graph

Basic blocks: Sequences of statements with single entry/exit
Flow edges: Conditional and unconditional control flow
Exception handling: Try/catch/finally flow modeling

Applications

Linting: Detect unused variables, undefined references, etc.
Transformation: Safe variable renaming and scope analysis
Analysis: Dead code detection, dependency analysis
IDE features: Go-to-definition, find references, refactoring

The semantic analyzer provides the deep program understanding needed for sophisticated JavaScript and TypeScript tooling.