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Hey folks I asked a separate query in the morning. I didnt get many responses. From there I have spent a ton of time learning the async/await, promises and callbacks to understand where I am going wrong. However I am still a little confused how to go about executing my logic. Here is my requirement

  1. My input is a string array of this form ["player1", "player2", "player3".... "player10"]
  2. I am running two for loops. The first for loop is starting from 0 and till end of array and the second for loop is starting from position 1. The idea is to take pairs together. So player 1 & player2 together. then player 1 and player 3, so on and so forth.

All this works fine.

Before the loop ends, i have two other requirements

  1. I need to go to another mongo collection with the pair of players and check something.
  2. Based on a certain condition, I need to save each pair in another collection.

I am using mongoose findOne to query. I want this entire loop to run synchronously that is pass each pair at a time, without completing the for loop first. However I dont know how to run that mongoose query synchronously.

I am also using NODE js

Can someone guide me please?

for (let i=0; i<namearray.length-1;){
                player1 = namearray[i];
                console.log('Hi I am here 4')
                console.log("Hi i am Player 1", player1)
                for(let j=0; j<namearray.length;){
                  if(j <= i){
                         j = i;
                         j++;
                         continue;
                       }
                       player2 = namearray[j]
                       console.log('Hi I am here 5')
                       console.log("Hi i am player 2", player2)
                       tournamentMatchRegister.findOne({$and:[{$or:[{Player1_Name : player1}, {Player2_Name : player2}]},
                              {$or:[{Player1_Name : player2}, {Player2_Name : player1}]}]},function(err,data9){
                                console.log('Hi I am here 6')
                                //console.log(data9)
                                console.log("Hi i am ", player1)
                                console.log("Hi i am ", player2)
                                //if(data2.Match_Completed === "No"){
                                  var newpotentialmatch = new scheduleRegister({
                                  //  Week_Number: weeknumber,
                                    Player1_Name: player1,
                                  //  Player1_Team: data2.Player1_TeamName,
                                  //  Player1_Seed: data2.PlayerSeedLevel,
                                    Player2_Name: player2,
                                  //  Player2_Team: data2.Player2_TeamName,
                                  //  Player2_Seed: data2.PlayerSeedLevel
                                  }); newpotentialmatch.save(function(err,data3){
                                    if(err){
                                      console.log(err)
                                    }
                                  })
                              })
                                                //  })

                j++
                }
              i++
            }
Sandeep Nair
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  • What have u tried in terms of code so far? Could you u update that in the question itself. – ambianBeing Jul 14 '20 at 12:55
  • updated...currently it takes the last pair into the findOne query, the rest of the pairs a redropped. I am guessing thats because of the asynchrous mature of node js...also sorry for all the console.logs – Sandeep Nair Jul 14 '20 at 12:58
  • Are u not using the result of `tournamentMatchRegister.findOne(...)`? `async/await` is what you are looking for here to achieve synchronous behaviour. Callbacks and promise chaining `.then(...)` could work as well, but they are verbose and can become messy. – ambianBeing Jul 14 '20 at 17:42

1 Answers1

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The for loop will complete unless you break out of it. If I'm understanding what you're trying to do, I think using callbacks would be the way forward. I think some of the answers here may be of help: Making mongoose.js queries run synchronously

stuckCode6
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