json2types

Convert JSON to TypeScript type definitions. Pipe it, pass a file, or grab from clipboard.

Install

npm install -g json2types

Or use directly with npx:

npx json2types input.json

Usage

# From a file
json2types data.json

# From stdin
echo '{"name": "Alice", "age": 30}' | json2types

# From clipboard
json2types --clipboard

# Custom root type name
json2types data.json --name User

Example

Input:

{
  "id": 1,
  "name": "Alice",
  "email": null,
  "address": {
    "street": "123 Main St",
    "city": "Springfield"
  },
  "tags": ["admin", "user"]
}

Output:

interface Address {
  street: string;
  city: string;
}

interface Root {
  id: number;
  name: string;
  email?: unknown;
  address: Address;
  tags: string[];
}

CLI Flags

Flag	Description
--name <name>, -n	Name for the root type (default: Root)
--clipboard, -c	Read JSON from system clipboard
--help, -h	Show help
--version, -v	Show version

Features

• Nested object detection with named interfaces
• Array element type inference
• Null values become optional properties
• Mixed-type arrays become union types
• Keys with special characters are quoted
• Zero runtime dependencies

License

MIT