DevBolt
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How do I convert TypeScript to JavaScript online?

Paste your TypeScript code and instantly get clean JavaScript with types, interfaces, enums, generics, access modifiers, and type assertions stripped. Options include converting enums to objects, removing comments, and preserving JSX. The tool uses a custom transpiler — no server needed. Everything runs in your browser.

Strip interface and types
Input
interface User {
  name: string;
  age: number;
}

const greet = (user: User): string => {
  return `Hello, ${user.name}`;
};
Output
const greet = (user) => {
  return `Hello, ${user.name}`;
};

TypeScript to JavaScript Converter

Strip TypeScript types, interfaces, enums, and generics to get clean JavaScript. Paste your .ts or .tsx code and get .js output instantly.

Samples:
.ts / .tsx

Ctrl+Enter to copy output · Conversion is instant as you type

Related Tools

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Tips & Best Practices

Pro Tip

TypeScript enums become runtime objects — consider const enums

Regular TypeScript enums compile to JavaScript objects with reverse mappings. const enums are inlined at compile time and produce no runtime code. When converting TS to JS, regular enum values become object lookups, while const enum values become literal constants.

Common Pitfall

Type-only imports disappear and may break side effects

TypeScript's type-only imports (import type { Foo }) are removed during compilation. But if you accidentally import a value as a type, the import disappears and any side effects from that module (polyfills, global registrations) stop executing. Use import type consistently to avoid confusion.

Real-World Example

Strip types to share code with non-TypeScript projects

Need to share a utility function with a JavaScript project? Convert it to JS rather than requiring the consumer to set up TypeScript. The core logic stays identical — you're just removing type annotations, interfaces, and generics to get portable JavaScript.

Security Note

TypeScript's type system provides no runtime safety

TypeScript types exist only at compile time. After conversion to JavaScript, there's no runtime validation. If your code relies on types to prevent invalid data (expecting a number but receiving a string), add runtime validation with Zod, io-ts, or manual checks at system boundaries.

Frequently Asked Questions

How does TypeScript to JavaScript conversion work?
The converter strips all TypeScript-specific syntax: type annotations, interfaces, type aliases, generics, access modifiers (public/private/protected), type assertions (as keyword), non-null assertions, and declare statements. Enum declarations are converted to equivalent JavaScript objects. Optional chaining and nullish coalescing are preserved as valid modern JavaScript. The output runs directly in any JavaScript runtime.
What happens to TypeScript enums when converted to JavaScript?
Numeric enums become immediately invoked functions creating bidirectional mapping objects. String enums become simpler one-directional objects. Const enums are inlined at every usage site and produce no runtime object. DevBolt's converter reproduces the same JavaScript output as the TypeScript compiler, ensuring identical runtime behavior.
What is the difference between type stripping and full transpilation?
Type stripping removes only TypeScript-specific syntax while preserving all JavaScript code as-is. Full transpilation also transforms modern JavaScript for older targets: converting async/await to promises, optional chaining to ternaries, etc. DevBolt performs type stripping by default, sufficient when your target supports modern JavaScript. Node.js 22+ includes native type stripping, running TypeScript files directly.

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