title: Removing duplicates in MongoDB
body: <p>Hi everyone i've been trying for days now to remove from my db all the duplicates that are in it. I've tried this solution that I found at this <a href="https://stackoverflow.com/questions/29072209/mongodb-duplicate-documents-even-after-adding-unique-key">Link</a> or at this one which is almost the same but unfortunately it returns the error that forEach is not a function. I don't understand why for them works and not for me even if the code is almost the same. Here's the code that i've tried so far</p>
  
  <pre><code>exports = function(payload, response) {
    const mongodb = context.services.get("mongodb-atlas");
    var obj=EJSON.parse(payload.body.text())
    var inserimentoDB = mongodb.db("test").collection("test0").insertMany(obj)
    var duplicates = [];
    mongodb.db("test").collection("test0").aggregate([
      { "$group": {
          "_id": { "Val": "$Val" },
          "dups": { "$push": "$_id" },
          "count": { "$sum": 1 }
      }},
      { "$match": { "count": { "$gt": 1 } }}
  ]).toArray().forEach(function(doc) {
      doc.dups.shift();
      mongodb.db("test").collection("test0").remove({ "_id": {"$in": doc.dups }});
  });
    }
  </code></pre>
  
  <p>I'm executing this code in a stitch function</p>