transchema

Transform JSON Schema definition into inline TypeScript type.

Usage

import { transform } from 'transchema'

transform({
  type: 'array',
  prefixItems: [
    { type: 'number' },
    { type: 'string' },
    { enum: ['Street', 'Avenue', 'Boulevard'] },
    { enum: ['NW', 'NE', 'SW', 'SE'] },
  ],
  items: { type: 'string' },
}) // [number, string, 'Street' | 'Avenue' | 'Boulevard', 'NW' | 'NE' | 'SW' | 'SE', ...string[]]

transform supports the following options:

• additionalProperties: additionalProperties for objects defaults to true in the JSON Schema specification, which means that all object types are non-closed. In this case, transchema will add & Record<string, unknown> union types to these objects to ensure semantic consistency. You can change its default value by setting additionalProperties: false to reduce the appearance of this type.

Why use it?

The typical scenario is to display type of a JSON Schema in the browser. This is useful for displaying MCP tool parameters.

Unlike other Json-Schema-to-TypeScript tools, it has:

• 0 runtime dependencies, so it's safe to run in the browser.
• Inline types generation, which will render human-readable types.

As such, modular combination features such as $ref are not supported.

Other Tools

• If you want to transform JSON Schema to a complete TypeScript declaration file, you can use json-schema-to-typescript-lite.
• If you use zod as the schema describer, zod-to-ts supports generating inline types.