Update collection to change the rank

Issue

i have a mongodb collection that I sort by the amount of points each item has, and it shows a rank according to it's place in the collection :

db.collection('websites').find({}).sort({  "points": -1 }).forEach(doc => {
    
  rank++;
  doc.rank = rank;
  delete doc._id;
  console.log(doc)

Si I thought to myself : Ok, I'm gonna update the rank in the collection, so I added this :

 db.collection('websites').updateMany({},
    { $set: { rank: doc.rank } }
)

But I was too good to be true, and it updates every single item with the same rank, which changes at each refresh, what exactly is going on, here ?

EDIT : I managed to do it by doing this :

rank = 0;

db.collection('websites').find({}).sort({  "points": -1 }).forEach(doc => {

  rank++;
  doc.rank = rank;
  //delete doc._id;
  console.log(doc._id);

  db.collection('websites').updateMany({_id : doc._id},
    { $set: { rank: doc.rank } },
    { upsert: true }
)

})

Solution

I managed to do it by doing:

rank = 0;

db.collection('websites').find({}).sort({  "points": -1 }).forEach(doc => {
  rank++;
  doc.rank = rank;
  //delete doc._id;
  console.log(doc._id);

  db.collection('websites').updateMany({_id : doc._id},
    { $set: { rank: doc.rank } },
    { upsert: true }
  )
})

Thank you everyone !

Answered By - Antoine Pascual