#Extension overview

Use this page when you want to extend schema-dsl but are not sure whether you need a custom DSL type, a validation keyword, runtime isolation, or plugin packaging.

The extension system has several layers. They can be combined, but they solve different jobs.

#Which extension should I use?

#Custom Extension Entries

The custom DSL type chapter owns DSL literals, s('...') seed builders, s.xxx() factories, parameters, and the decision not to expose custom base-builder methods for ordinary business types:

const schema = s({
  compact: 'tenant-id:corp!',
  named: s('tenant-id:corp!').label('Tenant'),
  typed: s.tenantId('corp').label('Tenant').require()
});

#Global and runtime-scoped extensions

Use the global schema-dsl/pure entry when an application has one extension set loaded at startup:

import { registerExtensions } from 'schema-dsl/pure';

export const s = registerExtensions([
  {
    literal: 'tenant-id',
    factoryName: 'tenantId',
    segmentMode: 'params',
    params: {
      scope: { kind: 'enum', values: ['tenant', 'corp'], default: 'tenant' }
    },
    schema({ scope }) {
      return {
        type: 'string',
        pattern: scope === 'corp' ? '^corp_[a-z0-9]+$' : '^tenant_[a-z0-9]+$'
      };
    }
  }
] as const);

Use schema-dsl/runtime when a framework, plugin host, tenant, test suite, or worker needs isolated extension state:

import { createRuntime } from 'schema-dsl/runtime';

const runtime = createRuntime();

runtime.registerExtensions([
  {
    literal: 'tenant-id',
    factoryName: 'tenantId',
    segmentMode: 'params',
    params: {
      scope: { kind: 'enum', values: ['tenant', 'corp'], default: 'tenant' }
    },
    schema({ scope }) {
      return {
        type: 'string',
        pattern: scope === 'corp' ? '^corp_[a-z0-9]+$' : '^tenant_[a-z0-9]+$'
      };
    }
  }
] as const);

#Recommended reading path

1. Read Custom DSL Types for reusable business types, parameters, and s.xxx() factories.
2. Read Custom Validation Keywords when the validator needs a new keyword.
3. Read Framework Integration before wiring extensions into a real application or framework.
4. Read Plugin Manager (Advanced) only when you need plugin lifecycle and hooks.

#Corresponding sample file

Example entry: extensions-overview.ts Note: Shows custom DSL type, runtime-scoped type, and validation keyword paths side by side.