TypeScript Formatter & Tester

Format TypeScript with Monaco syntax highlighting, compile with the TypeScript compiler loaded in your browser, review diagnostics with line messages, then execute the emitted JavaScript in a secure sandbox. Supports beautify, minify, validate, upload/download, and local history — compilation and execution stay on your device.

How to Use the TypeScript Formatter & Tester

Paste or upload TypeScript, format or validate it, compile in the browser, review diagnostics, and run the emitted JavaScript in the sandbox.

  1. Paste TypeScript into the input editor or upload a .ts / .tsx file.
  2. Set indentation and formatting options as needed.
  3. Click Beautify or Minify to format the TypeScript source, or Validate for a syntax-oriented check.
  4. Click Run to compile TypeScript, review diagnostics, and execute the emitted JavaScript.
  5. Read console logs, errors, emitted JS, and execution time in the sandbox panel below the editors.
  6. Copy or download formatted output, or restore a prior session from History.

Compile-then-run workflow

  • Run always compiles TypeScript first — fix red diagnostics before expecting clean execution.
  • Emitted JavaScript is what the sandbox executes; TypeScript types are erased at compile time.
  • Console output reflects runtime behavior of the compiled script.

Worked example

Load the sample typed function, click Run, and confirm console output and the emitted JavaScript appear. Introduce a type error, run again, and read the diagnostic message before fixing it.

Privacy

Compilation and execution stay in your browser. The TypeScript compiler bundle is fetched once per session; your source is not sent to ToolsLibrary servers for processing.

Limitations

This is a playground-style compiler — not a full project build with tsconfig paths, bundlers, or npm resolution. Large files may hit browser memory limits.

FAQ

Does compilation happen on a server?

No. The TypeScript compiler is downloaded and runs entirely in your browser when you format or click Run.

What happens when I click Run?

TypeScript is compiled to JavaScript, diagnostics are listed, and the emitted JS runs in a sandboxed iframe with console capture — similar to the JavaScript Formatter tester.

Can I see TypeScript compile errors before running?

Yes. After Run (or when compilation fails), diagnostics show TypeScript error messages. Fix issues in the editor and run again.

Does my TypeScript source leave the browser?

Formatting, compilation, and sandbox execution run locally. ToolsLibrary does not upload your source unless you explicitly save history while signed in.

What file extensions can I upload?

Upload .ts, .tsx, or plain text files via the file picker or drag-and-drop.

Can I view the emitted JavaScript?

Yes. After a successful Run, the sandbox panel shows the compiled JavaScript alongside console output and diagnostics.

What if the TypeScript compiler fails to load?

The tool shows a clear load error — usually a network issue blocking the compiler bundle. Refresh and try again on a stable connection.

Which TypeScript features are supported?

Standard TypeScript syntax including types, interfaces, enums, generics, and async/await. The in-browser compiler targets modern JavaScript emit suitable for the sandbox runner.

What is the difference between Beautify and Minify for TypeScript?

Beautify formats readable multi-line TypeScript. Minify compresses whitespace in the TypeScript source without compiling it.

What are the sandbox limits?

Run executes emitted JavaScript only — not arbitrary Node.js modules or unrestricted fetch. Use it to test typed snippets, not full application builds.