MongoDB Transactions doing NodeJS migrations | UpdateMany/Aggregate to replace all documents fields

Question

i'm trying to do NodeJS migrations and i'm a bit lost with mongodb transactions.

I have a db with 140 documents which are my users list and i want to change all fields structure.. I want to completely replace all actual documents with a new structure and new fields.

Well i already tested

coll.updateMany({}, {
  $set: {
    ...
  },
});

and

coll.aggregate([
  {
    $replaceWith: {
      ...
    },
  },
]);

Then migration is up in the console but there's no changes in the db, I don't know if i'm right and if i'm using good transactions.

I'm searching on MongoDB docs but it's not really clear for me

• https://www.mongodb.com/docs/manual/core/transactions/#transactions-and-operations
• https://www.mongodb.com/docs/manual/reference/operator/aggregation/replaceWith/#mongodb-pipeline-pipe.-replaceWith
• https://www.mongodb.com/docs/manual/reference/method/db.collection.updateMany/#std-label-updateMany-example-agg

If anyone can help me understand this syntax it would be great