feat(console): dispatch JSHandles as console arguments (#975)

This patch starts dispatching JSHandle instances as console arguments.

BREAKING CHANGE: this changes the API of the ConsoleMessage.

Fixes #324.

docs/api.md

@@ -1183,7 +1183,7 @@ Dialog's type, can be one of `alert`, `beforeunload`, `confirm` or `prompt`.
 [ConsoleMessage] objects are dispatched by page via the ['console'](#event-console) event.
 
 #### consoleMessage.args
-- <[Array]<[string]>>
+- <[Array]<[JSHandle]>>
 
 #### consoleMessage.text
 - <[string]>

lib/Page.js

@@ -331,7 +331,7 @@ class Page extends EventEmitter {
       event.args.map(arg => helper.releaseObject(this._client, arg));
       return;
     }
-    const values = await Promise.all(event.args.map(arg => helper.serializeRemoteObject(this._client, arg)));
+    const values = event.args.map(arg => this._frameManager.createJSHandle(event.executionContextId, arg));
     const text = values.join(' ');
     const message = new ConsoleMessage(event.type, text, values);
     this.emit(Page.Events.Console, message);

lib/helper.js

@@ -83,31 +83,6 @@ class Helper {
     return remoteObject.value;
   }
 
-  /**
-   * @param {!Session} client
-   * @param {!Object} remoteObject
-   * @return {!Promise<!Object>}
-   */
-  static async serializeRemoteObject(client, remoteObject) {
-    if (!remoteObject.objectId)
-      return Helper.valueFromRemoteObject(remoteObject);
-    if (remoteObject.subtype === 'promise')
-      return remoteObject.description;
-    try {
-      const response = await client.send('Runtime.callFunctionOn', {
-        objectId: remoteObject.objectId,
-        functionDeclaration: 'function() { return this; }',
-        returnByValue: true,
-      });
-      return response.result.value;
-    } catch (e) {
-      // Return description for unserializable object, e.g. 'window'.
-      return remoteObject.description;
-    } finally {
-      Helper.releaseObject(client, remoteObject);
-    }
-  }
-
   /**
    * @param {!Session} client
    * @param {!Object} remoteObject

test/test.js

@@ -695,9 +695,11 @@ describe('Page', function() {
         page.evaluate(() => console.log('hello', 5, {foo: 'bar'})),
         waitForEvents(page, 'console')
       ]);
-      expect(message.text).toEqual('hello 5 [object Object]');
+      expect(message.text).toEqual('hello 5 JSHandle@object');
       expect(message.type).toEqual('log');
-      expect(message.args).toEqual(['hello', 5, {foo: 'bar'}]);
+      expect(await message.args[0].jsonValue()).toEqual('hello');
+      expect(await message.args[1].jsonValue()).toEqual(5);
+      expect(await message.args[2].jsonValue()).toEqual({foo: 'bar'});
     }));
     it('should work for different console API calls', SX(async function() {
       const messages = [];
@@ -725,7 +727,7 @@ describe('Page', function() {
         'calling console.dir',
         'calling console.warn',
         'calling console.error',
-        'Promise',
+        'JSHandle@promise',
       ]);
     }));
     it('should not fail for window object', SX(async function() {
@@ -735,7 +737,7 @@ describe('Page', function() {
         page.evaluate(() => console.error(window)),
         waitForEvents(page, 'console')
       ]);
-      expect(message.text).toBe('Window');
+      expect(message.text).toBe('JSHandle@object');
     }));
   });