Database
db={coll:[{"_id":{"$oid":"65e9c7f87686dcd9e44e55c9"},"uid":"","techStack":["QgyHeSce","RrYcrkSv"]}],technologies:[{"uid":"RrYcrkSv","name":"Angular","url":"https://www.angular.io/"}]}
Query
db.coll.aggregate([{$lookup:{from:"technologies",localField:"techStack",foreignField:"uid",as:"technologies"}}])