Want to shorten links using bitly api with js

So, I am using Zapier for my High school project. in which inside the zapier it has a Node js server which provides a async fucntion to runs some codes. I want to shorten urls using javascript code in the code by zapier pathway so that any links provided will get shortened. Inputs have no problem . I get the links and can produce them in the output. but when i use js with bitly api unable to get an output . Errors encountered are : [object OBject] OR undefined.