ts-json-schema-generator

What is ts-json-schema-generator?

The ts-json-schema-generator package is a tool that generates JSON schemas from TypeScript types. It is useful for ensuring that your TypeScript types and JSON schemas stay in sync, which can be particularly helpful for validating JSON data against TypeScript interfaces or types.

What are ts-json-schema-generator's main functionalities?

Generate JSON Schema from TypeScript Interface

This feature allows you to generate a JSON schema from a TypeScript interface. You need to specify the path to your TypeScript file and the type you want to generate the schema for.

const { createGenerator } = require('ts-json-schema-generator');
const config = {
  path: 'path/to/your/file.ts',
  tsconfig: 'path/to/your/tsconfig.json',
  type: '*', // Or specify a particular type
};
const schema = createGenerator(config).createSchema(config.type);
console.log(JSON.stringify(schema, null, 2));

Generate JSON Schema for Specific Type

This feature allows you to generate a JSON schema for a specific TypeScript type. You need to specify the path to your TypeScript file and the type you want to generate the schema for.

const { createGenerator } = require('ts-json-schema-generator');
const config = {
  path: 'path/to/your/file.ts',
  tsconfig: 'path/to/your/tsconfig.json',
  type: 'MyType', // Specify the type you want to generate the schema for
};
const schema = createGenerator(config).createSchema(config.type);
console.log(JSON.stringify(schema, null, 2));

Generate JSON Schema with Custom Settings

This feature allows you to generate a JSON schema with custom settings. You can specify various options such as exposing all types, referencing the top-level schema, and using extended JSDoc annotations.

const { createGenerator } = require('ts-json-schema-generator');
const config = {
  path: 'path/to/your/file.ts',
  tsconfig: 'path/to/your/tsconfig.json',
  type: 'MyType',
  expose: 'all', // Expose all types
  topRef: true, // Reference the top-level schema
  jsDoc: 'extended', // Use extended JSDoc annotations
};
const schema = createGenerator(config).createSchema(config.type);
console.log(JSON.stringify(schema, null, 2));

Other packages similar to ts-json-schema-generator

typescript-json-schema

The typescript-json-schema package generates JSON schemas from TypeScript types. It is similar to ts-json-schema-generator but offers different configuration options and may have different performance characteristics.

json-schema-to-typescript

The json-schema-to-typescript package converts JSON schemas to TypeScript interfaces. While it performs the reverse operation of ts-json-schema-generator, it is often used in conjunction with it to ensure consistency between JSON schemas and TypeScript types.

ajv

The ajv package is a JSON schema validator that can be used to validate JSON data against JSON schemas. While it does not generate schemas from TypeScript types, it is often used alongside ts-json-schema-generator to validate data against the generated schemas.

README

ts-json-schema-generator

Extended version of https://github.com/xiag-ag/typescript-to-json-schema.

Inspired by YousefED/typescript-json-schema. Here's the differences list:

• this implementation avoids the use of typeChecker.getTypeAtLocation() (so probably it keeps correct type aliases)
• processing AST and formatting JSON schema have been split into two independent steps
• not exported types, interfaces, enums are not exposed in the definitions section in the JSON schema

Contributors

This project is made possible by a community of contributors. We welcome contributions of any kind (issues, code, documentation, examples, tests,...). Please read our code of conduct.

Usage

npm install --save ts-json-schema-generator
./node_modules/.bin/ts-json-schema-generator --path 'my/project/**.*.ts' --type 'My.Type.Full.Name'

Options

-p, --path 'index.ts'
    The path to the TypeScript source file. If this is not provided, the type will be searched in the project specified in the `.tsconfig`.

-t, --type 'My.Type.Full.Name'
    The type the generated schema will represent. If omitted, the generated schema will contain all
    types found in the files matching path. The same is true if '*' is specified.

-e, --expose <all|none|export>
    all: Create shared $ref definitions for all types.
    none: Do not create shared $ref definitions.
    export (default): Create shared $ref definitions only for exported types.

-f, --tsconfig 'my/project/tsconfig.json'
    Use a custom tsconfig file for processing typescript (see https://www.typescriptlang.org/docs/handbook/tsconfig-json.html) instead of the default:
    {
        "compilerOptions": {
            "noEmit": true,
            "emitDecoratorMetadata": true,
            "experimentalDecorators": true,
            "target": "ES5",
            "module": "CommonJS",
            "strictNullChecks": false,
        }
    }

-r, --no-top-ref
    Do not create a top-level $ref definition.

-j, --jsDoc <extended|none|basic>
    none: Do not use JsDoc annotations.
    basic: Read JsDoc annotations to provide schema properties.
    extended (default): Also read @nullable, and @asType annotations.

-u, --unstable
    Do not sort properties.

-s, --strict-tuples
    Do not allow additional items on tuples.

-c, --no-type-check
    Skip type checks for better performance.

-k, --validationKeywords
    Provide additional validation keywords to include.

Current state

• interface types
• enum types
• union, tuple, type[] types
• string, boolean, number types
• "value", 123, true, false, null, undefined literals
• type aliases
• generics
• typeof
• keyof
• conditional types

Run locally

yarn --silent run run --path 'test/valid-data/type-mapped-array/*.ts' --type 'MyObject'

Debug

yarn --silent run debug --path 'test/valid-data/type-mapped-array/*.ts' --type 'MyObject'

And connect via the debugger protocol.

AST Explorer is amazing for developers of this tool!