Section 2.5.5Source: server/src/parser/extractors/SymbolExtractor.ts

TypeScript Type Declarations

Extracting compile-time type definitions including interfaces, type aliases, and enums from Babel syntax trees.

Source: server/src/parser/extractors/SymbolExtractor.ts

Supported TypeScript Types

CodeGraph extracts three core TypeScript type declarations as first-class symbols:

Declaration Type	SymbolKind	Example Syntax	Runtime Scope Binding?
TSInterfaceDeclaration	interface	interface UserRecord { id: string; }	No (stripped at runtime)
TSTypeAliasDeclaration	typeAlias	type Handler = (e: Event) => void	No (stripped at runtime)
TSEnumDeclaration	enum	enum Direction { Up, Down }	Yes (runtime object in JS)

Why Type Declarations Require Name-Based Fallbacks

Because TypeScript interfaces and type aliases are purely compile-time constructs, Babel's scope tracking (path.scope.getBinding(name)) does not create runtime binding records for them.

When an export or implements statement references a type (e.g. export default UserInterface orclass A implements UserInterface), the resolver falls back to searching parsedFile.symbolsby identifier name:

Type Binding Fallback

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// Fallback when Babel scope binding returns undefined for types:
const symbol = parsedFile.symbols.find(
    s => s.name === name && (
        s.symbolKind === "interface" ||
        s.symbolKind === "typeAlias" ||
        s.symbolKind === "enum"
    )
);

2.5.4 Variables & Destructuring Patterns

2.5.6 Object Properties & Methods