Refactor JavaScript dialog API

This patch introduces a Dialog class and a new 'dialog'
event instead of the 'alert', 'beforeunload', 'confirm' and
'prompt' events and 'Page.handleDialog' method.

Fixes #2.

lib/Dialog.js

@@ -0,0 +1,69 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+class Dialog {
+    /**
+     * @param {!Connection} client
+     * @param {!Dialog.Type} type
+     * @param {string} message
+     */
+    constructor(client, type, message) {
+        this._client = client;
+        this.type = type;
+        this._message = message;
+        this._handled = false;
+    }
+
+    /**
+     * @return {string}
+     */
+    message() {
+        return this._message;
+    }
+
+    /**
+     * @param {string=} promptText
+     * @return {!Promise}
+     */
+    async accept(promptText) {
+        console.assert(!this._handled, 'Cannot accept dialog which is already handled!');
+        this._handled = true;
+        await this._client.send('Page.handleJavaScriptDialog', {
+            accept: true,
+            promptText: promptText
+        });
+    }
+
+    /**
+     * @return {!Promise}
+     */
+    async dismiss() {
+        console.assert(!this._handled, 'Cannot dismiss dialog which is already handled!');
+        this._handled = true;
+        await this._client.send('Page.handleJavaScriptDialog', {
+            accept: false
+        });
+    }
+}
+
+Dialog.Type = {
+    Alert: 'alert',
+    BeforeUnload: 'beforeunload',
+    Confirm: 'confirm',
+    Prompt: 'prompt'
+};
+
+module.exports = Dialog;

lib/Page.js

@@ -19,6 +19,7 @@ var EventEmitter = require('events');
 var helpers = require('./helpers');
 var mime = require('mime');
 var Request = require('./Request');
+var Dialog = require('./Dialog');
 
 class Page extends EventEmitter {
     /**
@@ -228,17 +229,18 @@ class Page extends EventEmitter {
     }
 
     _onDialog(event) {
-        var eventType = null;
+        var dialogType = null;
         if (event.type === 'alert')
-            eventType = Page.Events.Alert;
+            dialogType = Dialog.Type.Alert;
         else if (event.type === 'confirm')
-            eventType = Page.Events.Confirm;
+            dialogType = Dialog.Type.Confirm;
         else if (event.type === 'prompt')
-            eventType = Page.Events.Prompt;
+            dialogType = Dialog.Type.Prompt;
         else if (event.type === 'beforeunload')
-            eventType = Page.Events.BeforeUnload;
-        if (eventType)
-            this.emit(eventType, event.message);
+            dialogType = Dialog.Type.BeforeUnload;
+        console.assert(dialogType, 'Unknown javascript dialog type: ' + event.type);
+        var dialog = new Dialog(this._client, dialogType, event.message);
+        this.emit(Page.Events.Dialog, dialog);
     }
 
     /**
@@ -563,12 +565,9 @@ function convertPrintParameterToInches(parameter) {
 }
 
 Page.Events = {
-    Alert: 'alert',
-    BeforeUnload: 'beforeunload',
-    Confirm: 'confirm',
     ConsoleMessage: 'consolemessage',
+    Dialog: 'dialog',
     Exception: 'exception',
-    Prompt: 'prompt',
     ResourceLoadingFailed: 'resourceloadingfailed',
     ResponseReceived: 'responsereceived',
 };

phantom_shim/WebPage.js

@@ -63,6 +63,7 @@ class WebPage {
         this._pageEvents.on(PageEvents.ConsoleMessage, msg => (this.onConsoleMessage || noop).call(null, msg));
         this._pageEvents.on(PageEvents.Confirm, message => this._onConfirm(message));
         this._pageEvents.on(PageEvents.Alert, message => this._onAlert(message));
+        this._pageEvents.on(PageEvents.Dialog, dialog => this._onDialog(dialog));
         this._pageEvents.on(PageEvents.Exception, (exception, stack) => (this._onError || noop).call(null, exception, stack));
     }
 
@@ -195,16 +196,6 @@ class WebPage {
         this._onConfirmCallback = handler;
     }
 
-    /**
-     * @param {string} message
-     */
-    _onConfirm(message) {
-        if (!this._onConfirmCallback)
-            return;
-        var accept = this._onConfirmCallback.call(null, message);
-        await(this._page.handleDialog(accept));
-    }
-
     /**
      * @return {(function()|undefined)}
      */
@@ -222,13 +213,16 @@ class WebPage {
     }
 
     /**
-     * @param {string} message
+     * @param {!Dialog} dialog
      */
-    _onAlert(message) {
-        if (!this._onAlertCallback)
-            return;
-        this._onAlertCallback.call(null, message);
-        await(this._page.handleDialog(true));
+    _onDialog(dialog) {
+        if (dialog.type === 'alert' && this._onAlertCallback) {
+            this._onAlertCallback.call(null, dialog.message());
+            await(dialog.accept());
+        } else if (dialog.type === 'confirm' && this._onConfirmCallback) {
+            var result = this._onConfirmCallback.call(null, dialog.message());
+            await(result ? dialog.accept() : dialog.dismiss());
+        }
     }
 
     /**

test/test.js

@@ -155,6 +155,27 @@ describe('Puppeteer', function() {
             expect(failedResources).toBe(1);
         }));
     });
+
+    describe('Page.Events.Dialog', function() {
+        it('should fire', function(done) {
+            page.on('dialog', dialog => {
+                expect(dialog.type).toBe('alert');
+                expect(dialog.message()).toBe('yo');
+                done();
+            });
+            page.evaluate(() => alert('yo'));
+        });
+        // TODO Enable this when crbug.com/718235 is fixed.
+        xit('should allow accepting prompts', SX(async function(done) {
+            page.on('dialog', dialog => {
+                expect(dialog.type).toBe('prompt');
+                expect(dialog.message()).toBe('question?');
+                dialog.accept('answer!');
+            });
+            var result = await page.evaluate(() => prompt('question?'));
+            expect(result).toBe('answer!');
+        }));
+    });
 });
 
 // Since Jasmine doesn't like async functions, they should be wrapped