🚀 JSON to TypeScript Interfaces

Convert JSON into TypeScript types instantly — inside VS Code. Handles messy json as well, repairs and then converts into typescript type.

No context switching. No online tools. Just select JSON and generate types in seconds.

✨ Features

• ⚡ Convert JSON → TypeScript types instantly
• 🎯 Works on selected JSON or entire file
• 🧠 Smart type inference (objects, arrays, primitives)
• ✏️ Editable type name (no more T pain)
• 📌 Cursor placed exactly where you need to edit
• 🧩 Seamless VS Code integration

📦 Installation

From VS Code Marketplace

Search for:

JSON to TypeScript Interfaces

Manual (Development)

git clone https://github.com/YOUR_USERNAME/json-to-typescript-interfaces.git
cd json-to-typescript-interfaces
npm install

Then press:

F5

🚀 Usage

1. Open a JSON file

{
  "name": "Aryan",
  "age": 24,
  "isActive": true
}

2. Select JSON (or leave unselected for full file)

3. Run command

1. select the json
2. Ctrl + Shift + T

or

1. select the json
2. Ctrl + Shift + P
3. search for "Generate TypeScript from JSON" and hit enter

✅ Output

type T = {
  name: string;
  age: number;
  isActive: boolean;
}

👉 The type name is pre-selected — just start typing to rename.

🧠 How It Works

• Parses selected JSON
• Infers TypeScript types
• Generates a clean type definition
• Inserts it directly into your editor with smart cursor positioning

🎯 Example

Input

{
  "user": {
    "id": 1,
    "name": "John"
  },
  "tags": ["dev", "ts"]
}

Output

type T = {
  user: { id: number; name: string; };
  tags: string[];
}

🧠 Handles Messy JSON (Powered by relax-json)

Real-world JSON is rarely perfect.

Logs, LLM outputs, and APIs often return invalid or sloppy JSON like:

{
  a: lam,
  c: "2",
  d: 3,
}

❌ This would normally crash JSON.parse

✨ What this extension does differently

Before generating types, it automatically repairs malformed JSON using relax-json.

It intelligently fixes:

• Unquoted keys → "a"
• Single quotes → "value"
• Unquoted string values → "lam"
• Trailing commas
• Comments (// and /* */)

🔧 Example

Input (invalid JSON)

{
  a: lam,
  c: "2",
  d: 3,
}

Internally repaired to:

{
  "a": "lam",
  "c": "2",
  "d": 3
}

Final Output

type T = {
  a: string;
  c: string;
  d: number;
}

🚀 Why this matters

Most tools fail on anything that isn’t perfectly valid JSON.

This extension:

• ✅ Recovers broken JSON automatically
• ✅ Works with real-world data (not just ideal inputs)
• ✅ Saves time debugging tiny syntax issues

⚠️ Note

Repair is best-effort, not magic:

• Extremely broken structures may still fail
• Always review generated types for critical systems

⚠️ Limitations (v1)

• Mixed-type arrays are simplified ((string | number)[] not yet supported)
• No optional field detection yet
• Nested types are inlined (no separate interfaces)

🛣️ Roadmap

• [ ] Optional field detection
• [ ] JSON schema support

🤝 Contributing

Contributions are welcome!

git clone https://github.com/YOUR_USERNAME/json-to-typescript-interfaces.git

Open an issue or submit a PR 🚀

⭐ Support

If you find this useful:

• ⭐ Star the repo
• 🐦 Share with other devs
• 🧠 Suggest improvements

📄 License

MIT

💡 Why this exists

Because switching to random websites to convert JSON → TS breaks flow.

This extension keeps you in the zone.

Made with ❤️ for developers