Updated on December 21, 2016: The issue has been resolved in protractor version 4.0.14.
protractor relies on selenium-webdriver:
'@types/selenium-webdriver': '~2.53.31',
Unfortunately, a recent merge (version 2.53.37) caused an issue as mentioned in this link.
A temporary solution is to manually install version 2.53.36 to resolve the issue until a new protractor version with the updated selenium-webdriver package is released.
npm install @types/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="95e6f0f9f0fbfce0f8b8e2f0f7f1e7fce3f0e7d5a7bba0a6bba6a3">[email protected]</a> --save-dev
Remember to remove the dev dependency once protractor is fixed.
There is a pending pull request at: https://github.com/angular/protractor/pull/3848