feat(expectedConditions): added expectedConditions.numberOfElementsToBe

lib/expectedConditions.ts

@@ -1,6 +1,9 @@
 import {error as wderror} from 'selenium-webdriver';
+
 import {ProtractorBrowser} from './browser';
-import {ElementFinder} from './element';
+import {ElementArrayFinder, ElementFinder} from './element';
+import {element} from './index';
+import {Locator} from './locators';
 import {falseIfMissing, passBoolean} from './util';
 
 /**
@@ -434,4 +437,23 @@ export class ProtractorExpectedConditions {
       return elementFinder.isSelected().then(passBoolean, falseIfMissing);
     });
   }
+
+  /**
+   * An expectation for checking the number of elements with given locator
+   *
+   * @example
+   * var EC = protractor.ExpectedConditions;
+   * browser.wait(EC.numberOfElementsToBe(by.repeater('cat in pets'), 3), 5000);
+   *
+   * @param {Locator} locator The locator to be used
+   * @param {number} numberElem The expected number of elements
+   * @returns {!function} An expected condition that returns a promise
+   *     representing whether the size of elements list is equal to defined.
+   */
+  numberOfElementsToBe(locator: Locator, numberElem: number): Function {
+    return () => {
+      let elemArray: ElementArrayFinder = element.all(locator);
+      return elemArray.count().then((count) => count === numberElem);
+    };
+  }
 }

spec/basic/expected_conditions_spec.js

@@ -176,6 +176,12 @@ describe('expected conditions', function() {
     expect(EC.or(EC.not(valid), EC.and(valid, invalid)).call()).toBe(false);
   });
 
+  it('should have numberOfElementsToBe', function() {
+    var loc = by.model('username');
+    expect(EC.numberOfElementsToBe(loc, 1).call()).toBe(true);
+    expect(EC.numberOfElementsToBe(loc, 0).call()).toBe(false);
+  });
+
   describe('for forked browsers', function() {
     // ensure that we can run EC on forked browser instances
     it('should have alertIsPresent', function() {