Friend recommendation get mutual friends

Users
2

Something like this should work for you.

{
 me as var(func: uid(0x1)) {
  sc as math(1) # Give a score of 1 to the user
  fr as friend {
   friend {
    fscore as math(sc)  # This will be number of common friends
   }
  }
 }

# Get top ten people with highest score
 TopRecommendations(func: uid(fscore), orderdesc: val(fscore), first: 10) @filter(not uid(fr,me)) { # Remove the user and his friends
  name
  # Fetch the friends of recommendations and intersect with the friends of uid(0x1) to get list of mutual friends.
  friend @filter(uid(fr)) {
    uid
    name
  }
 }
}

Also, there was a some problem in your data-set which I have rectified and shared the updated data-set below.


{
    "set": [
        {
            "name": "A",
            "uid": "0x1",
            "friend": [
                {
                    "name": "B",
                    "uid": "0x2"
                },
                {
                    "name": "C",
                    "uid": "0x3"
                },
                {
                    "name": "E",
                    "uid": "0x5"
                }
            ]
        },
        {
            "name": "B",
            "uid": "0x2",
            "friend": [
                {
                    "name": "D",
                    "uid": "0x4"
                }
            ]
        },
        {
            "name": "C",
            "uid": "0x3",
            "friend": [
                {
                    "name": "D",
                    "uid": "0x4"
                }
            ]
        },
        {
            "name": "D",
            "uid": "0x4",
            "friend": [
                {
                    "name": "B",
                    "uid": "0x2"
                },
                {
                    "name": "C",
                    "uid": "0x3"
                }
            ]
        },
        {
            "name": "E",
            "uid": "0x5",
            "friend": [
                {
                    "name": "A",
                    "uid": "0x1"
                },
                {
                    "name": "F",
                    "uid": "0x6"
                }
            ]
        },
        {
            "name": "F",
            "uid": "0x6",
            "friend": [
                {
                    "name": "E",
                    "uid": "0x5"
                }
            ]
        }
    ]
}

Note - How node D was connected to itself i.e. to a node with name C but uid as 0x4 which caused inconsistencies in the query result.