JS to TS Converter
Convert JavaScript to TypeScript
Source Input
Processed Output
What is the JS to TS Converter?
The JS to TS converter parses your JavaScript and adds TypeScript annotations: function parameters get inferred types, object literals become interfaces, and class fields are typed. It handles common patterns like destructuring, async functions, and exports.
Frequently Asked Questions (FAQ)
Q: Does it handle complex generics?
It adds foundational types. For advanced generics (conditional types, mapped types), you should refine the output manually after conversion.
Q: Is my code sent to a server?
No. The conversion runs entirely in your browser using a static transformation engine. Your code never leaves your machine.
How to Use the JS to TS Converter
- 1Paste your input into the editor above — or start from the preloaded example.
- 2Adjust any options, then click Run to process instantly in your browser.
- 3Review the output panel, then copy, download, or save it as a reusable snippet.