[js] Add WebElement.takeScreenshot()

Fixes #958

Author: jleyba

javascript/node/selenium-webdriver/CHANGES.md

@@ -1,3 +1,7 @@
+## v2.49.0-dev
+
+* Added `WebElement#takeScreenshot()`.
+
 ## v2.48.1
 
 * FIXED: Adjusted how the control flow tracks promise callbacks to avoid a

javascript/node/selenium-webdriver/package.json

@@ -1,6 +1,6 @@
 {
   "name": "selenium-webdriver",
-  "version": "2.48.1",
+  "version": "2.49.0-dev",
   "description": "The official WebDriver JavaScript bindings from the Selenium project",
   "license": "Apache-2.0",
   "keywords": [

javascript/webdriver/command.js

@@ -163,6 +163,7 @@ webdriver.CommandName = {
   ELEMENT_EQUALS: 'elementEquals',
 
   SCREENSHOT: 'screenshot',
+  TAKE_ELEMENT_SCREENSHOT: 'takeElementScreenshot',
   IMPLICITLY_WAIT: 'implicitlyWait',
   SET_SCRIPT_TIMEOUT: 'setScriptTimeout',
   SET_TIMEOUT: 'setTimeout',

javascript/webdriver/http/http.js

@@ -283,6 +283,8 @@ webdriver.http.Executor.COMMAND_MAP_ = (function() {
           get('/session/:sessionId/element/:id/css/:propertyName')).
       put(webdriver.CommandName.ELEMENT_EQUALS,
           get('/session/:sessionId/element/:id/equals/:other')).
+      put(webdriver.CommandName.TAKE_ELEMENT_SCREENSHOT,
+          get('/session/:sessionId/element/:id/screenshot')).
       put(webdriver.CommandName.SWITCH_TO_WINDOW,
           post('/session/:sessionId/window')).
       put(webdriver.CommandName.MAXIMIZE_WINDOW,

javascript/webdriver/webdriver.js

@@ -2187,6 +2187,25 @@ webdriver.WebElement.prototype.isDisplayed = function() {
 };
 
 
+/**
+ * Take a screenshot of the visible region encompassed by this element's
+ * bounding rectangle.
+ *
+ * @param {boolean=} opt_scroll Optional argument that indicates whether the
+ *     element should be scrolled into view before taking a screenshot. Defaults
+ *     to false.
+ * @return {!webdriver.promise.Promise.<string>} A promise that will be
+ *     resolved to the screenshot as a base-64 encoded PNG.
+ */
+webdriver.WebElement.prototype.takeScreenshot = function(opt_scroll) {
+  var scroll = !!opt_scroll;
+  return this.schedule_(
+      new webdriver.Command(webdriver.CommandName.TAKE_ELEMENT_SCREENSHOT)
+          .setParameter('scroll', scroll),
+      'WebElement.takeScreenshot(' + scroll + ')');
+};
+
+
 /**
  * Schedules a command to retrieve the outer HTML of this element.
  * @return {!webdriver.promise.Promise.<string>} A promise that will be