Protractor is a test framework for Angular JS applications which uses Selenium to automate the browser i.e Protractor also uses JS but still communicates with Selenium using WebDriverJS. It only supports TypeScript.
Protractor is open source framework specifically for automation of AngularJS applications although it can be used to automate non-angular web based applications. So in case your application is designed using AngularJS for the front end, so it would be recommended to use Protractor. And also if your Selenium test framework is designed with all the waits , so you can also use selenium to automate so that you can choose your favorite programming language to write the test script .
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