TypeScript to JS Converter — Free Strip Types Online
Strip TypeScript types and emit clean JavaScript. Free, instant, browser-only. Pick target ES version (ES5, ES2017, ESNext).
About TypeScript to JavaScript Converter
A TypeScript-to-JavaScript converter removes type annotations and emits plain JS — useful for: showing TS code to a JS-only audience, embedding snippets where TS isn't supported, debugging compiled output, learning what TS adds vs JS, and quick removal of TS for prototyping in JS-only contexts. The ZTools TypeScript to JS Converter uses the official TypeScript compiler with configurable target (ES5 / ES2017 / ES2020 / ESNext), preserves comments, supports React TSX → JSX, and handles modern features (decorators, async/await, optional chaining).
Use cases
- StackOverflow / blog where TS isn't welcome. Question/answer audience expects JS. Quick conversion strips types without manual work.
- Quick prototyping in JS sandbox. CodePen, JSFiddle don't support TS without setup. Strip types, paste, run.
- Learning TypeScript. See how TS code compiles to JS — understand what types add (none at runtime) and what TS does at compile time.
- Debugging compile output. Suspect a TS bug? See exactly what JS is being emitted; check for unexpected transformations.
How it works
- Paste TypeScript. Standalone code, modules, classes, JSX/TSX all supported.
- Pick target ES version. ES5 (legacy compat), ES2017 (async/await native), ES2020 (optional chaining native), ESNext (latest).
- Pick module system. ES modules / CommonJS / UMD / None.
- Convert. TypeScript compiler removes types, optionally lowers syntax to target ES version.
- Copy / download. .js file ready to use.
Examples
Input: `function add(a: number, b: number): number { return a + b; }`
Output: `function add(a, b) { return a + b; }` — types removed.
Input: TSX: `const Btn = (props: { label: string }) => <button>{props.label}</button>`
Output: JSX: `const Btn = (props) => <button>{props.label}</button>` — types stripped, JSX preserved.
Input: Class with private fields, ES5 target
Output: IIFE-wrapped function with prototype methods — full lowering for old browsers.
Frequently asked questions
Why does the output differ between targets?
TS lowers modern syntax to older equivalents. Target ES5: async/await becomes generator + Promise polyfill. Target ESNext: keep async/await as-is.
Are decorators preserved?
Yes — TS Stage 3 decorators emit cleanly to ES2022+. For earlier targets, lowered to function calls.
Will my JSX still work?
TSX → JSX strips types; JSX itself is preserved. Use a JSX-aware bundler (Vite, Webpack) to compile JSX → React.createElement calls.
What about type-only imports?
Removed entirely — they have no runtime effect. `import type { User }` becomes nothing.
Will the JS run identically?
Yes — TS types are erased at compile, so the JS behaves the same. Only edge case: enum / namespace / decorator emit JS code that didn't exist in TS source.
How is this different from `tsc`?
Same compiler, browser-friendly UI. For a project, run `tsc` from CLI; for one-off conversion, this tool.
Pro tips
- Pick target ESNext for modern dev; ES5 only for legacy browser support.
- Type-only imports (`import type`) are tree-shaken automatically.
- JSX preserved — use a JSX bundler downstream.
- For libraries, ship both: `.ts` source + compiled `.js` + `.d.ts` declarations.
- For runtime-checked types, TS doesn't help — use Zod / io-ts / etc. for runtime validation.
Reviewed by Ahsan Mahmood · Last updated 2026-05-06 · Part of ZTools.
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