How compare arraylist string’s value similary on MongoDB?

I want to find a mean to compare each “adref” value for each iteration if is already present on DB or not, but unfortunately I don’t have enough capacity to be able to approve my code because js doesn’t has my basic programming language, so could someone help me understand better ?

const jList = [];

let info = {
     title: elem.title,
     description: elem.description,
     adref: elem.adref
     }
     
jList.push(info)


for (let info of jList) {
    if ((jList.element.adref) === db.MyCollection.find(jList.element.adref.valueOf()))
        print("item is already existed")
         continue;
          }
    else:
        print("item is not existed")
        db.MyCollection.insertMany( { title: elem.title, description: elem.title, adref: elem.adref,} )
        continue;
      }