How can I set up common functions that are available for my test suites with Protractor / Selenium?

To reuse code i use the page object pattern. I put the page object in a separate file and in a module.

For example, the pages.js file contains some page objects.

'use strict';(function() {  var Application = function() {    var app = this;    browser.get('http://localhost:9003/');    app.login = function() {      element(by.buttonText('login')).click();      return new LoginPage();    };    var LoginPage = function() {      var loginPage = this;      loginPage.withCredentials = function(login, password) {        element(by.css('.loginField')).Keys(login);        element(by.css('.passwordField')).Keys(password);        element(by.buttonText('login')).click();        return new WelcomePage();      };    };    var WelcomePage = function() {      var welcomePage = this;      welcomePage.getGreetings = function() {        return element(by.css('.greetings')).getText();      };    };  };  module.exports = function() {    return new Application();  };}());

and i import them in my acceptance test using require:

'use strict';var Application = require('./pages.js');describe('The application', function() {  it('should let you log into the application', function() {    var application = new Application();    var welcomePage = application.login().withCredentials('Jean', '!sz3sk,dz');    expect(welcomePage.getGreetings()).toEqual('Welcome Jean');  });});