json-to-schema-converter v2.0.1

JSON to Schema Converter

A TypeScript library for automatically generating JSON Schema from JSON objects or strings.

Features

• Convert any valid JSON to a JSON Schema
• Automatic detection of common string formats (date-time, email, URI, UUID)
• Support for all JSON Schema draft versions (07, 2019-09, 2020-12)
• Smart handling of arrays with mixed types
• Intelligent merging of object schemas
• Proper handling of required properties
• TypeScript type definitions included
• Zero dependencies

Installation

Using npm:

npm install json-to-schema-converter

Using pnpm:

pnpm add json-to-schema-converter

Using yarn:

yarn add json-to-schema-converter

Usage

Basic Usage

import { jsonToSchema } from "json-to-schema-converter";

// Your JSON string
const jsonString = `{
  "name": "John Doe",
  "age": 30,
  "isActive": true,
  "email": "john.doe@example.com",
  "birthDate": "1990-01-01"
}`;

// Generate schema with default options
const schema = jsonToSchema(jsonString);

console.log(JSON.stringify(schema, null, 2));

With Custom Options

import { jsonToSchema } from "json-to-schema-converter";

const jsonString = `{
  "name": "John Doe",
  "email": "john.doe@example.com"
}`;

// Generate schema with custom options
const schema = jsonToSchema(jsonString, {
  detectFormat: true,
  schemaVersion: "2020-12",
});

console.log(JSON.stringify(schema, null, 2));

Working with JavaScript Objects

import { generateJsonSchema } from "json-to-schema-converter";

// Work directly with JavaScript objects
const data = {
  users: [
    { id: 1, name: "Alice", active: true },
    { id: 2, name: "Bob", active: false },
  ],
};

// Generate schema from object
const schema = generateJsonSchema(data);

console.log(JSON.stringify(schema, null, 2));

API Reference

jsonToSchema(jsonString, options?)

Parses a JSON string and generates a JSON Schema.

Parameters:

• jsonString: A valid JSON string
• options: Optional configuration (see Options section)

Returns: A JSON Schema object

generateJsonSchema(value, options?)

Generates a JSON Schema from a JavaScript value.

Parameters:

• value: Any JavaScript value (object, array, primitive, etc.)
• options: Optional configuration (see Options section)

Returns: A JSON Schema object

mergeObjectSchemas(schemas)

Merges multiple object schemas into one.

Parameters:

• schemas: Array of object schemas to merge

Returns: A merged JSON Schema object

Options

How it works

The library analyzes the structure and types of your JSON data and generates an appropriate JSON Schema that describes it. It handles:

• All primitive types (strings, numbers, booleans, null)
• Objects with properties and required fields
• Arrays (homogeneous and heterogeneous)
• Nested structures
• Common string formats
• Mixed type detection with oneOf schemas

Advanced Features in v2.0.0

• Improved Array Handling: Better detection of array item types, including mixed-type arrays
• Smart Schema Merging: Intelligently merges object schemas to create more accurate representations
• Required Property Detection: Properly identifies which properties should be marked as required
• Schema Deduplication: Removes duplicate schemas to create cleaner output

License

MIT

Contributing

Contributions are welcome! Here's how you can contribute to this project:

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

When you submit a PR, GitHub Actions will automatically run tests on your code to ensure everything works correctly. The workflow runs tests on multiple Node.js versions (16.x, 18.x, 20.x) to ensure compatibility.

Continuous Integration

This project uses GitHub Actions for continuous integration:

• Automated Testing: All tests are run automatically on push to main and on pull requests
• Code Coverage: Test coverage reports are generated and uploaded to Codecov
• Multi-environment Testing: Tests run on multiple Node.js versions

Test Results

The badges at the top of this README show the current status of tests:

• The general "Tests" badge shows the overall status of the latest workflow run
• Individual Node.js version badges (16, 18, 20) show the status for each Node.js version
• The Codecov badge shows the current code coverage percentage

You can click on any badge to see more detailed information about the test runs.

Author

Reza Shahnazar (@rezashahnazar)