Making mongo's aggregation pipeline case insenstive

I am using mongo's aggregation pipeline to do a search on a collection.

Here is my filter condition:

filter := bson.D{
		{"$project", bson.D{
			{"names", bson.D{
				{"$filter", bson.D{
					{"input", "$names"},
					{"as", "names"},
					{"cond", bson.D{
						{"$and", bson.A{
							bson.D{{"$eq", bson.A{"$$names.firstname", "John"}}},
                            bson.D{{"$eq", bson.A{"$$names.lastname", "Doe"}}},
						}},
					}},
				}},
			}},
		}},
	}

This filter works well but it is case sensitive. If pass john instead of John, it returns 0 documents. How do I make firstname and lastname case insenstive?

You can use $regexMatch into $filter like this:

Note that I've used Regex ^name$ to match only the word, you can use the regex you want, but with option i, the regex is case insensitive.

db.collection.aggregate([
  {
    "$project": {
      "names": {
        "$filter": {
          "input": "$names",
          "as": "names",
          "cond": {
            "$and": [
              {
                "$regexMatch": {
                  "input": "$$names.firstname",
                  "regex": "^John$",
                  "options": "i"
                }
              },
              {
                "$regexMatch": {
                  "input": "$$names.lastname",
                  "regex": "^Doe$",
                  "options": "i"
                }
              }
            ]
          }
        }
      }
    }
  }
])

Example here