title: Is there a way to resolve multiple promises with Protractor?
body: <p>I have this:</p>
  
  <pre><code>element(by.id('x')).sendKeys('xxx').then(function(text) {
    element(by.id('y')).sendKeys('yyy').then(function(text) {
       element(by.id('z')).sendKeys('zzz').then(function(text) {
          expect(element(by.id('myButton')).isEnabled()).toBe(true);
       })
    });
  });
  </code></pre>
  
  <p>The button 'myButton' is enabled when the elements 'x', 'y' and 'z' all have values. It's my understanding that sendKeys returns a promise. </p>
  
  <p>So is this the only way that I can check if 'myButton' which depends on data in all the three fields is enabled?</p>