@continuum/adapters

Protocol adapter layer for the Continuum SDK.

Transforms external UI schema formats into Continuum's ViewDefinition and NodeValue shapes. Ships with a built-in adapter for Google's A2UI (Agent-to-User Interface) protocol.

Installation

npm install @continuum/adapters

ProtocolAdapter Interface

interface ProtocolAdapter<TExternalView, TExternalData = unknown> {
  name: string;
  toView(external: TExternalView): ViewDefinition;
  fromView?(snapshot: ViewDefinition): TExternalView;
  toState?(externalData: TExternalData): Record<string, NodeValue>;
  fromState?(state: Record<string, NodeValue>): TExternalData;
}

| Method | Required | Description | |---|---|---| | name | yes | Identifier for this adapter (for example, a2ui) | | toView | yes | Convert external view format into a ViewDefinition | | fromView | no | Convert a ViewDefinition back to external format | | toState | no | Convert external data payload into Continuum NodeValue map | | fromState | no | Convert Continuum state map back to external data format |

Built-in: A2UI Adapter

a2uiAdapter transforms Google A2UI JSON into Continuum nodes.

import { a2uiAdapter } from '@continuum/adapters';

const view = a2uiAdapter.toView({
  id: 'my-form',
  version: '1.0',
  fields: [
    { name: 'email', type: 'TextInput', label: 'Email' },
    { name: 'agree', type: 'Switch', label: 'I Agree' },
  ],
});

// Use with a session
session.pushView(view);

Type Mapping

| A2UI Type | Continuum Node Type | dataType | |---|---|---| | TextInput | field | string | | TextArea | field | string | | Dropdown | field | string | | SelectionInput | field | string | | Switch | field | boolean | | Toggle | field | boolean | | DateInput | field | string | | Section | group | n/a | | Card | group | n/a | | unknown | field | string |

A2UI Types

interface A2UIForm {
  id?: string;
  version?: string;
  title?: string;
  fields: A2UIField[];
}

interface A2UIField {
  name?: string;
  type: A2UIFieldType | string;
  label?: string;
  options?: A2UIOption[];
  fields?: A2UIField[];
}

interface A2UIOption {
  id: string;
  label: string;
}

type A2UIFieldType =
  | 'TextInput'
  | 'TextArea'
  | 'Dropdown'
  | 'SelectionInput'
  | 'Switch'
  | 'Toggle'
  | 'DateInput'
  | 'Section'
  | 'Card';

Round-trip

const form: A2UIForm = { fields: [{ name: 'email', type: 'TextInput' }] };

const view = a2uiAdapter.toView(form);
const backToForm = a2uiAdapter.fromView(view);

const state = a2uiAdapter.toState({ email: '[email protected]', agree: true });
const backToData = a2uiAdapter.fromState(state);

Utility Exports

createDefaultNodeValue(dataType)

Returns a default NodeValue value for the provided data type.

createDefaultNodeValue('boolean'); // { value: false }
createDefaultNodeValue('number'); // { value: 0 }
createDefaultNodeValue('string'); // { value: '' }
createDefaultNodeValue('any-unknown'); // { value: '' }

valueForDataType

Alias for createDefaultNodeValue.

const defaultValue = valueForDataType('number');

Writing a Custom Adapter

import type { ProtocolAdapter } from '@continuum/adapters';
import type { ViewDefinition, NodeValue } from '@continuum/contract';

interface MyFormat {
  widgets: { uid: string; kind: string }[];
}

export const myAdapter: ProtocolAdapter<MyFormat> = {
  name: 'my-protocol',

  toView(external: MyFormat): ViewDefinition {
    return {
      viewId: 'my-app',
      version: '1.0',
      nodes: external.widgets.map((w) => ({
        id: w.uid,
        type: 'field',
        key: w.uid,
        dataType: 'string',
      })),
    };
  },
};

Links

• Root README
• Integration Guide: Building a Protocol Adapter