There is a function called evaluate(). Find an element in the dom and then run the expression.

For example. If you want to count the number of todos in the http://angularjs.org/ website (under Add Some Control), do this:

Open the element explorer in protractor

./node_modules/protractor/bin/elementexplorer.js

browser.get('http://angularjs.org/')

element(by.model('todoText')).evaluate('todos.length').

  then(function(count) {

    console.log(count)

  });

It should give you a 2

You can also use executeAsyncScript

browser.executeAsyncScript(function(callback) {

  // Here we use document.body, but your app may live under a different

  // element.

  var service = angular.element(document.body)

      .injector()

      .get('myService');

  service.query({}, function(data) {

    callback(data);

  });

}).then(function (output) {

  console.log(output);

});

See an example: https://github.com/andresdominguez/protractor-meetup/blob/master/test/e2e/api-helper.js