Why not Jest instead of Moch and Chai?

Hi smart ppl,

I have a question regarding the ‘testing’ portion of the Full stack development course. I have many dev. friends and all of them recommended that I learn Jest instead of Mocha + chai. for now, I skipped testing completely. now I don’t know what to do. if I learn jest course instead, will I not have any problems? in other words, is knowing Mocha +chai necessary for me to go on with the full stack dev path?
Thank you in advance for our help!