Abstract Syntax Tree
An AST is a tree-shaped abstract representation of the syntactic structure of source code, where each node represents a syntactic construct — the compiler's core data structure.
Purpose
A standard representation of program structure, used for compilation, analysis, transformation, and tooling.
Mechanism
The parser builds the AST from a token stream. Node types include declarations, expressions, statements, and patterns. AST traversal is used for type checking, optimization, and code generation. Babel/ESLint transform and analyze JS via the AST.
Use cases
- Compiler implementation
- Code tooling
- Static analysis