feat: Add the autofill.trigger command

src/bidiMapper/BidiNoOpParser.ts

@@ -16,6 +16,7 @@
  */
 
 import type {
+  Autofill,
   Browser,
   BrowsingContext,
   Cdp,
@@ -33,6 +34,13 @@ import type {
 import type {BidiCommandParameterParser} from './BidiParser.js';
 
 export class BidiNoOpParser implements BidiCommandParameterParser {
+  // Autofill module
+  // keep-sorted start block=yes
+  parseAutofillTriggerParams(params: unknown): Autofill.TriggerParameters {
+    return params as Autofill.TriggerParameters;
+  }
+  // keep-sorted end
+
   // Bluetooth module
   // keep-sorted start block=yes
   parseDisableSimulationParameters(

src/bidiMapper/BidiParser.ts

@@ -16,6 +16,7 @@
  */
 
 import type {
+  Autofill,
   Bluetooth,
   Browser,
   BrowsingContext,
@@ -31,6 +32,11 @@ import type {
 } from '../protocol/protocol.js';
 
 export interface BidiCommandParameterParser {
+  // Autofill module
+  // keep-sorted start block=yes
+  parseAutofillTriggerParams(params: unknown): Autofill.TriggerParameters;
+  // keep-sorted end
+
   // Bluetooth module
   // keep-sorted start block=yes
   parseDisableSimulationParameters(

src/bidiMapper/CommandProcessor.ts

@@ -32,6 +32,7 @@ import type {Result} from '../utils/result.js';
 import {BidiNoOpParser} from './BidiNoOpParser.js';
 import type {BidiCommandParameterParser} from './BidiParser.js';
 import type {MapperOptions} from './MapperOptions.js';
+import {AutofillProcessor} from './modules/autofill/AutofillProcessor.js';
 import type {BluetoothProcessor} from './modules/bluetooth/BluetoothProcessor.js';
 import {BrowserProcessor} from './modules/browser/BrowserProcessor.js';
 import type {ContextConfigStorage} from './modules/browser/ContextConfigStorage.js';
@@ -66,6 +67,7 @@ interface CommandProcessorEventsMap extends Record<string | symbol, unknown> {
 
 export class CommandProcessor extends EventEmitter<CommandProcessorEventsMap> {
   // keep-sorted start
+  #autofillProcessor: AutofillProcessor;
   #bluetoothProcessor: BluetoothProcessor;
   #browserCdpClient: CdpClient;
   #browserProcessor: BrowserProcessor;
@@ -105,6 +107,7 @@ export class CommandProcessor extends EventEmitter<CommandProcessorEventsMap> {
     this.#logger = logger;
 
     this.#bluetoothProcessor = bluetoothProcessor;
+    this.#autofillProcessor = new AutofillProcessor(browsingContextStorage);
 
     // keep-sorted start block=yes
     this.#browserProcessor = new BrowserProcessor(
@@ -165,8 +168,17 @@ export class CommandProcessor extends EventEmitter<CommandProcessorEventsMap> {
     command: ChromiumBidi.Command,
   ): Promise<ChromiumBidi.ResultData> {
     switch (command.method) {
+      // Autofill module
+      // keep-sorted start block=yes
+      case 'autofill.trigger':
+        return await this.#autofillProcessor.trigger(
+          this.#parser.parseAutofillTriggerParams(command.params),
+        );
+      // keep-sorted end
+
       // Bluetooth module
       // keep-sorted start block=yes
+
       case 'bluetooth.disableSimulation':
         return await this.#bluetoothProcessor.disableSimulation(
           this.#parser.parseDisableSimulationParameters(command.params),

src/bidiMapper/modules/autofill/AutofillProcessor.ts

@@ -0,0 +1,104 @@
+/**
+ * Copyright 2025 Google LLC.
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import type {CdpClient} from '../../../cdp/CdpClient.js';
+import {
+  type Autofill,
+  type EmptyResult,
+  NoSuchNodeException,
+  UnsupportedOperationException,
+} from '../../../protocol/protocol.js';
+import type {BrowsingContextStorage} from '../context/BrowsingContextStorage.js';
+import {parseSharedId} from '../script/SharedId.js';
+
+/**
+ * Responsible for handling the `autofill` module.
+ */
+export class AutofillProcessor {
+  readonly #browsingContextStorage: BrowsingContextStorage;
+
+  constructor(browsingContextStorage: BrowsingContextStorage) {
+    this.#browsingContextStorage = browsingContextStorage;
+  }
+
+  /**
+   * Triggers autofill for a specific element with the provided field data.
+   *
+   * @param params Parameters for the autofill.trigger command
+   * @returns An empty result
+   */
+  async trigger(params: Autofill.TriggerParameters): Promise<EmptyResult> {
+    try {
+      // Get the browsing context from the parameters
+      const context = this.#browsingContextStorage.getContext(params.context);
+
+      // Parse the shared ID to get frame, document, and backend node ID
+      const parsedSharedId = parseSharedId(params.element.sharedId);
+      if (parsedSharedId === null) {
+        throw new NoSuchNodeException(
+          `SharedId "${params.element.sharedId}" was not found.`,
+        );
+      }
+
+      const {frameId, documentId, backendNodeId} = parsedSharedId;
+
+      // Assert that the frame matches the current context (if frameId is available)
+      if (frameId !== undefined && frameId !== params.context) {
+        throw new NoSuchNodeException(
+          `SharedId "${params.element.sharedId}" belongs to different frame. Current frame is ${params.context}.`,
+        );
+      }
+
+      // Assert that the document matches the current context's navigable ID
+      if (context.navigableId !== documentId) {
+        throw new NoSuchNodeException(
+          `SharedId "${params.element.sharedId}" belongs to different document. Current document is ${context.navigableId}.`,
+        );
+      }
+
+      // Cast to `any` as a temporary workaround for prototyping, since the TypeScript types
+      // for CDP in "Chromium BiDi" aren't automatically updated with local changes.
+
+      // Based on the Autofill.pdl definition, call the correct CDP method
+      // The PDL shows: command trigger with fieldId as DOM.BackendNodeId
+
+      // First, we need to enable the Autofill domain
+      try {
+        await context.cdpTarget.cdpClient.sendCommand('Autofill.enable');
+      } catch (enableErr) {
+        console.log('Failed to enable Autofill domain:', (enableErr as Error).message);
+      }
+
+      // Call the trigger method with the correct parameters from PDL
+      await (context.cdpTarget.cdpClient as any).sendCommand('Autofill.trigger', {
+        fieldId: backendNodeId, // DOM.BackendNodeId from parsed shared ID
+        frameId: frameId, // Page.FrameId from parsed shared ID
+        card: params.card,  // optional CreditCard
+        address: params.address, // optional Address
+      });
+
+      return {};
+    } catch (err) {
+      if ((err as Error).message.includes('command was not found')) {
+        throw new UnsupportedOperationException(
+          'Autofill.trigger() is not supported by this browser',
+        );
+      }
+      throw err;
+    }
+  }
+}

src/bidiTab/BidiParser.ts

@@ -16,6 +16,7 @@
  */
 import type {BidiCommandParameterParser} from '../bidiMapper/BidiMapper.js';
 import type {
+  Autofill,
   Bluetooth,
   Browser,
   BrowsingContext,
@@ -32,6 +33,13 @@ import type {
 import * as Parser from '../protocol-parser/protocol-parser.js';
 
 export class BidiParser implements BidiCommandParameterParser {
+  // Autofill module
+  // keep-sorted start block=yes
+  parseAutofillTriggerParams(params: unknown): Autofill.TriggerParameters {
+    return Parser.Autofill.parseTriggerParameters(params);
+  }
+  // keep-sorted end
+
   // Bluetooth module
   // keep-sorted start block=yes
   parseDisableSimulationParameters(