When a user opens the JS file, RAA encrypts files on the computer and demands a ransom of around $250 to get the files back. At the moment, the RAA ransomware is primarily spread in Russia.
RAA is currently being distributed via emails as attachments that pretend to be doc files and have names like mgJaXnwanxlS_doc_.js. When the JS file is opened it will encrypt the computer and then demand a ransom of ~$250 USD to get the files back. To make matters worse, it will also extract the embedded password stealing malware called Pony from the JS file and install it onto the onto the victim's computer.
Full details on how RAA works and how you can protect yourself can be found over here.