TypeScript to Declaration (.d.ts) Converter
Paste TypeScript source, implementation included, to instantly generate its real .d.ts declaration file using the TypeScript compiler's own declaration emitter. Free online developer tool.
Paste TypeScript
Type Declaration (.d.ts)
Declaration output will appear here...
Free TypeScript to Declaration (.d.ts) Converter
Paste TypeScript source — implementation code included, not just type declarations — to instantly generate its real .d.ts declaration file using the TypeScript compiler's own declaration emitter.
How to Use It
Paste TypeScript source into the input box, or click "Load Example." The tool spins up an in-memory TypeScript compiler program with declaration emit enabled and no JavaScript output, then returns exactly what tsc --declaration --emitDeclarationOnly would produce for that file — function bodies and other implementation details are stripped, leaving only the exported signatures and types.
Example
Given export function add(a: number, b: number): number { return a + b; } and export interface Point { x: number; y: number; }, the tool emitsexport declare function add(a: number, b: number): number; andexport interface Point { x: number; y: number; } — the function body is gone, and only the type-level signatures remain.
Common Use Cases
- Checking what public API surface a module exposes before publishing a package.
- Generating a quick
.d.tspreview for a single file without configuring a full build. - Reviewing exactly which types a piece of code exports at the declaration level.
FAQs
Is this a real declaration emit, or an approximation?
It's a real emit — this tool runs an actual TypeScript compiler program against your source withdeclaration: true and emitDeclarationOnly: true, the same flagstsc uses to generate .d.ts files, rather than a hand-written approximation.
Why did I get an error instead of output?
Declaration emit requires syntactically valid TypeScript. If your input has a syntax error, the tool surfaces the compiler's own diagnostic message so you can fix the specific issue.
Is my TypeScript uploaded anywhere?
No — compilation happens entirely client-side in your browser, using the TypeScript compiler loaded on demand. Nothing you paste is sent to a server.