ts-xsd

W3C XSD 1.1 parser, builder, and TypeScript type inference — a 1:1 TypeScript representation of XML Schema Definition.

Why

Working with XSD schemas in TypeScript usually means hand-maintaining types that drift from the source of truth. ts-xsd closes that gap:

• Parse any W3C XSD 1.1 schema into a typed Schema object — no invented properties, no shortcuts.
• Infer TypeScript types at compile time from schema literals via InferSchema<T>.
• Generate TypeScript interfaces at build time when schemas are too complex for compile-time inference.
• Round-trip XSD → Schema → XSD with semantic preservation.
• Parse/build XML documents against a schema definition.

Installation

npm install @abapify/ts-xsd
# or
pnpm add @abapify/ts-xsd
# or
bun add @abapify/ts-xsd

Runtime dependency: @xmldom/xmldom (DOM parsing). ts-morph and zod are required for codegen features.

Quick Start

Parse and Build XSD

import { parseXsd, buildXsd } from '@abapify/ts-xsd';

// Parse XSD to typed Schema object
const schema = parseXsd(`
  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="person" type="PersonType"/>
    <xs:complexType name="PersonType">
      <xs:sequence>
        <xs:element name="name" type="xs:string"/>
        <xs:element name="age" type="xs:int" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:schema>
`);

// Build back to XSD
const xsd = buildXsd(schema, { pretty: true });

Type Inference from Schema Literals

import type { InferSchema } from '@abapify/ts-xsd';

const personSchema = {
  element: [{ name: 'person', type: 'PersonType' }],
  complexType: [
    {
      name: 'PersonType',
      sequence: {
        element: [
          { name: 'name', type: 'xs:string' },
          { name: 'age', type: 'xs:int', minOccurs: 0 },
        ],
      },
    },
  ],
} as const;

// Infer TypeScript type at compile time — no runtime cost
type Person = InferSchema<typeof personSchema>;
// => { name: string; age?: number }

Parse and Build XML with a Schema

import { parseXml, buildXml } from '@abapify/ts-xsd';

const xml = `<person><name>John</name><age>30</age></person>`;
const data = parseXml(personSchema, xml);
// => { person: { name: 'John', age: 30 } }

const rebuilt = buildXml(personSchema, data, { xmlDecl: false });
// => <person><name>John</name><age>30</age></person>

Generate TypeScript Interfaces from XSD

import { parseXsd, generateInterfaces } from '@abapify/ts-xsd';

const schema = parseXsd(xsdContent);
const { code } = generateInterfaces(schema, {
  flatten: true, // Inline all nested types into one
  addJsDoc: true, // Add JSDoc comments
  rootTypeName: 'MySchema',
});

// code is a ready-to-write .ts file:
// export type MySchema = { person: { name: string; age?: number } };

API Reference

XSD Module

import {
  parseXsd,
  buildXsd,
  resolveImports,
  loadSchema,
  type Schema,
} from '@abapify/ts-xsd';

parseXsd(xsd: string): Schema

Parse an XSD XML string into a typed Schema object.

buildXsd(schema: Schema, options?: BuildOptions): string

Build an XSD XML string from a Schema object.

const xsd = buildXsd(schema, {
  prefix: 'xs', // Namespace prefix (default: 'xs')
  pretty: true, // Pretty print (default: true)
  indent: '  ', // Indentation string
});

resolveImports(schema, availableSchemas): Schema

Resolve and link imported schemas by matching import.schemaLocation to $filename. Returns a new schema with $imports populated.

const base = { ...parseXsd(baseXsd), $filename: 'base.xsd' };
const orders = { ...parseXsd(ordersXsd), $filename: 'orders.xsd' };

const linked = resolveImports(orders, [base]);
// linked.$imports = [base]

loadSchema(schemaPath: string, options?: LoaderOptions): Schema

Load and parse an XSD file from disk. Synchronous. Set autoLink: true to automatically resolve imports, or autoResolve: true to merge everything into one schema.

const schema = loadSchema('/path/to/schema.xsd', { autoLink: true });

Infer Module

import type { InferSchema, InferElement, SchemaLike } from '@abapify/ts-xsd';

InferSchema<T>

Infer a TypeScript type from a schema literal (as const). Returns a union of all root element types.

InferElement<T, Name>

Infer the type for a specific root element by name.

type Person = InferElement<typeof schema, 'person'>;

Built-in Type Mapping

XML Module

import { parseXml, buildXml } from '@abapify/ts-xsd';

parseXml<T>(schema, xml: string): T

Parse an XML string into a typed object using a schema definition.

buildXml<T>(schema, data: T, options?: XmlBuildOptions): string

Build an XML string from a typed object using a schema definition. Defaults to xmlDecl: true (includes <?xml ...?> declaration); pass { xmlDecl: false } for bare output.

Codegen Module

import { generateSchemaLiteral, generateInterfaces } from '@abapify/ts-xsd';

generateSchemaLiteral(xsd: string, options?): string

Generate a TypeScript as const schema literal from XSD content — for use with InferSchema<T>.

const code = generateSchemaLiteral(xsdContent, {
  name: 'PersonSchema',
  features: { $xmlns: true, $filename: true },
  exclude: ['annotation'],
});
// export const PersonSchema = { ... } as const;

generateInterfaces(schema: Schema, options?): { code: string }

Generate TypeScript interfaces from a parsed schema. Useful when schemas are too complex for compile-time InferSchema<T> (TypeScript TS2589 recursion limits).

const { code } = generateInterfaces(schema, {
  flatten: true, // Inline all nested types (default: false)
  addJsDoc: true, // JSDoc comments
  rootTypeName: 'MySchema',
});

CLI

The package ships a CLI for code generation:

# Config-based (recommended) — uses ts-xsd.config.ts in cwd
npx ts-xsd codegen

# Single-file mode
npx ts-xsd codegen person.xsd
npx ts-xsd codegen person.xsd ./generated/person-schema.ts
npx ts-xsd codegen person.xsd --name=PersonSchema

Config-Based Generation

For multi-schema projects, use the composable generator system:

import {
  defineConfig,
  rawSchema,
  interfaces,
} from '@abapify/ts-xsd/generators';

export default defineConfig({
  sources: {
    base: {
      xsdDir: 'schemas',
      outputDir: 'src/generated',
      schemas: ['base'],
    },
    orders: {
      xsdDir: 'schemas',
      outputDir: 'src/generated',
      schemas: ['orders'],
      autoLink: true,
    },
  },
  generators: [rawSchema(), interfaces({ flatten: true })],
});

Schema Structure

The Schema type is a 1:1 TypeScript representation of W3C XSD. Non-W3C extension properties are prefixed with $:

interface Schema {
  targetNamespace?: string;
  elementFormDefault?: 'qualified' | 'unqualified';

  // Composition
  import?: Import[];
  include?: Include[];

  // Declarations
  element?: TopLevelElement[];
  complexType?: TopLevelComplexType[];
  simpleType?: TopLevelSimpleType[];
  group?: NamedGroup[];
  attributeGroup?: NamedAttributeGroup[];

  // Extensions (non-W3C, prefixed with $)
  $xmlns?: { [prefix: string]: string }; // Namespace prefix mappings
  $imports?: Schema[]; // Linked imported schemas
  $filename?: string; // Source filename (for round-trip)
}

Cross-Schema Type Resolution

Link schemas via $imports to resolve types across schema boundaries:

const base = { ...parseXsd(baseXsd), $filename: 'base.xsd' };
const orders = { ...parseXsd(ordersXsd), $filename: 'orders.xsd' };

const linked = resolveImports(orders, [base]);

// InferSchema can now resolve types from `base`
type OrderData = InferSchema<typeof linked>;

Design Principles

1. Pure W3C XSD 1.1 — types match the official XMLSchema.xsd exactly; no invented properties.
2. Type-safe — full TypeScript support with compile-time inference.
3. Minimal dependencies — @xmldom/xmldom for DOM parsing, ts-morph and zod for codegen.
4. Tree-shakeable — import only what you need.
5. Round-trip verified — tested against the official W3C XMLSchema.xsd.

References

• W3C XML Schema 1.1 Part 1: Structures
• XMLSchema.xsd
• Codegen Guide

License

MIT