JavaScript to Typescript (2026) ✨
Convert JS object to TypeScript types in browser REPL. Free, no signup. By Folioify.
JavaScript to Typescript Tool 🧰
Paste your input below and the output will update automatically.
TL;DR ⚡
Use JS Object to TypeScript when you have object-shaped data and need a quick starting point for interfaces or type aliases.
Example Input
{
user: { id: 1, name: "Kai" },
roles: ["admin", "editor"]
}Expected Output
type Root = {
user: {
id: number;
name: string;
};
roles: string[];
};Core Information 📌
Pricing
Free — no registration required.
Data Handling
Client-side only — runs in your browser.
Output
Instant conversion with clean results.
Target Users
Developers, designers, and creators.
What is JavaScript to Typescript? 🧭
JS Object to TypeScript infers TypeScript shapes from JavaScript object literals so copied examples can become typed models.
What can it do? ✅
- Infer strings, numbers, booleans, arrays, and nested object structures.
- Generate TypeScript-friendly names and property types.
- Use examples from config, API responses, or state objects.
- Create a fast draft that can be refined manually.
How JavaScript to Typescript works (Step-by-Step) 🪄
- Step 1: Paste a JavaScript object literal.
- Step 2: The converter reads the value shape and maps it to TypeScript types.
- Step 3: Review the output and rename fields or root types as needed.
Common Errors
- Mixed arrays may infer broad union or unknown-style types.
- Function values are not useful for structural JSON-like type inference.
- A single sample may miss optional fields that appear in real data.
Limitations
- Generated types should be reviewed before production use.
- Optional fields require multiple samples or manual edits.
- Runtime validation is not included.
Free vs Paid 💸
This tool is 100% free with no usage limits or account required. You can use it for quick conversions without subscriptions or payments.
Official vs Third-Party 🧪
Folioify provides this as a third-party utility. It does not replace official tools, but offers a fast, accessible alternative for everyday workflows.
Use Cases 💡
- Create initial types from a copied object sample.
- Type frontend state objects during refactors.
- Document object-shaped configuration with TypeScript.
Frequently Asked Questions ❓
Can it detect optional fields?
A single object sample cannot reliably prove optional fields. Add them manually after generation.
Does it generate runtime validators?
No. Use a Zod converter when you need runtime validation schemas.
Can I use API response examples?
Yes. Paste representative response data and review the generated types.
Data Sources & Disclaimer 📎
This tool is provided for educational and productivity purposes. Output accuracy depends on input quality. It relies on well-known open-source libraries where applicable.
Last updated: July 4, 2026. This page is maintained regularly so tool details, examples, and FAQs stay current for developers and AI search systems.