javascript/atoms/locators/classname.js

// Copyright 2010 WebDriver committers
// Copyright 2010 Google Inc.
//
// 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.

goog.provide('bot.locators.className');

goog.require('goog.array');
goog.require('goog.dom');
goog.require('goog.dom.DomHelper');
goog.require('goog.string');


/**
 * Tests whether the standardized W3C Selectors API are available on an
 * element.
 * @param {!(Document|Element)} root The document or element to test for CSS
 *     selector support.
 * @return {boolean} Whether or not the root supports query selector APIs.
 * @see http://www.w3.org/TR/selectors-api/
 * @private
 */
bot.locators.className.canUseQuerySelector_ = function(root) {
  return !!(root.querySelectorAll && root.querySelector);
};


/**
 * Find an element by its class name.
 * @param {string} target The class name to search for.
 * @param {!(Document|Element)} root The document or element to perform the
 *     search under.
 * @return {Element} The first matching element found in the DOM, or null if no
 *     such element could be found.
 */
bot.locators.className.single = function(target, root) {
  if (!target) {
    throw Error('No class name specified');
  }

  target = goog.string.trim(target);
  if (target.split(/\s+/).length > 1) {
    throw Error('Compound class names not permitted');
  }

  // Closure will not properly escape class names that contain a '.' when using
  // the native selectors API, so we have to handle this ourselves.
  if (bot.locators.className.canUseQuerySelector_(root)) {
    return root.querySelector('.' + target.replace(/\./g, '\\.')) || null;
  }
  var elements = goog.dom.getDomHelper(root).getElementsByTagNameAndClass(
      /*tagName=*/'*', /*className=*/target, root);
  return elements.length ? elements[0] : null;
};


/**
 * Find an element by its class name.
 * @param {string} target The class name to search for.
 * @param {!(Document|Element)} root The document or element to perform the
 *     search under.
 * @return {!goog.array.ArrayLike} All matching elements, or an empty list.
 */
bot.locators.className.many = function(target, root) {
  if (!target) {
    throw Error('No class name specified');
  }

  target = goog.string.trim(target);
  if (target.split(/\s+/).length > 1) {
    throw Error('Compound class names not permitted');
  }

  // Closure will not properly escape class names that contain a '.' when using
  // the native selectors API, so we have to handle this ourselves.
  if (bot.locators.className.canUseQuerySelector_(root)) {
    return root.querySelectorAll('.' + target.replace(/\./g, '\\.'));
  }
  return goog.dom.getDomHelper(root).getElementsByTagNameAndClass(
      /*tagName=*/'*', /*className=*/target, root);
};