JS2TS
JS2TS - your ultimate code conversion companion is an AI-powered tool that quickly converts Javascript code into Typescript, automating the process with a simple and intuitive interface.
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What is JS2TS?
JS2TS is an AI-powered online tool that automatically converts JavaScript code to TypeScript with full type annotations, interfaces, generics, and type safety. The tool uses artificial intelligence to infer types from code context, usage patterns, and naming conventions, transforming plain .js files into fully typed .ts files in seconds rather than hours of manual work.
Key features include automatic conversion of function parameter types, return type annotations, object interfaces, array and tuple types, union and intersection types, generic type parameters, class property types, async/Promise return types, module import/export types, React component props, type inference from usage, and enum declarations. The converter supports ES6+ syntax, CommonJS, and ESModules, and handles both React components (.jsx to .tsx) with typed props and state, and Node.js modules with typed exports.
JS2TS is designed for JavaScript developers looking to migrate to TypeScript, teams working on large codebases who need better type safety, frontend developers integrating API responses, and developers learning TypeScript syntax. It's particularly valuable for project migration, API integration, refactoring and modernization, and educational purposes where developers can see how their JS translates to TS.
JS2TS pricing
Pricing model: Free
Completely free to use. No account, login, or credit card required. Unlimited conversions with no hidden costs, subscription plans, or usage limitations.
JS2TS pros
- Completely free with no hidden costs or limitations
- Zero setup required - works entirely online
- No login or account required to use
- AI-powered intelligent conversion that infers types automatically
- Adds type annotations, interfaces, and generics instantly
- Converts code in seconds instead of hours of manual work
- Handles large JavaScript files and codebases
- Supports React components with typed props and state
- Supports Node.js modules with typed exports
- Processes conversions in real time
- Code is never stored or logged on servers
- Works with ES6+, CommonJS, and ESModules syntax
- Catches errors at compile time before production
- Better IDE support with autocomplete and inline docs
- Zero runtime overhead - TypeScript compiles to plain JavaScript
- Safer refactoring with typed interfaces
- Self-documenting code via type signatures
- Handles JSX syntax, hooks, and async patterns
- Unlimited conversions with no usage limits
- Intuitive interface easy for any developer to use
JS2TS cons
- For very large codebases, must paste sections incrementally
- Complex or ambiguous cases may fallback to any or unknown types
- Manual refinement needed for fallback types
- Web-based only - no offline or CLI version
- Requires copying code between editor and browser
- May not handle all edge cases perfectly
- No batch conversion for multiple files at once
- Dependent on AI accuracy for type inference
Frequently asked questions about JS2TS
What is a JavaScript to TypeScript converter?
A JavaScript to TypeScript converter is a tool that automatically adds static type annotations to existing JS code. It converts JS files to TS by inferring types from usage patterns and adding explicit type declarations, interfaces, and generics — turning plain .js files into fully typed .ts files.
How do I convert JavaScript to TypeScript?
Paste your JS code into the JS2TS converter, click Convert, and copy the typed output. The AI adds type annotations, interfaces, and generics automatically. For manual conversion, rename .js to .ts and add type annotations by hand — AI converters do this in seconds.
Is this JS to TS converter free?
Yes, completely free. No account, login, or credit card required. Paste JavaScript, click Convert, copy TypeScript — unlimited conversions with no hidden costs or limitations.
What TypeScript patterns does the converter support?
The AI-powered JS to TS converter handles: function parameter and return types, object interfaces, array types, union and intersection types, generics, type inference, class definitions, async/await return types, and module exports — covering the most common JavaScript-to-TypeScript migration patterns.
Can I convert large JavaScript files?
Yes. JS2TS handles large files. For very large codebases, paste sections incrementally for best results. Works with ES6+ syntax, CommonJS, and ESModules.
Does JS2TS store my code?
No. Conversions are processed in real time and your code is never stored or logged on our servers.
Why convert JS to TS?
TypeScript adds compile-time error detection, better IDE autocomplete, self-documenting code via type signatures, and safer refactoring. It catches bugs before runtime — especially valuable in larger codebases and team projects.
What is the difference between JavaScript and TypeScript?
TypeScript is a superset of JavaScript that adds optional static typing. All valid JavaScript is valid TypeScript. TypeScript adds type annotations, interfaces, enums, and generics that are stripped at compile time — the output is plain JavaScript. The key benefit is catching type errors during development, not at runtime.
How accurate is AI-powered JS to TS conversion?
JS2TS uses AI to infer types from code context, usage patterns, and naming conventions. It produces accurate types for most common patterns. For complex or ambiguous cases, it uses TypeScript's any or unknown as a safe fallback — which you can refine manually.
Does JS2TS work with React and Node.js code?
Yes. JS2TS converts React components (.jsx to .tsx) with typed props and state, and Node.js modules with typed exports and function signatures. It handles JSX syntax, hooks, and async patterns common in both ecosystems.