findOrCreate in Loopback model

Question

I found an interesting problem on loopback. I was confused when I was adding records with findOrCreate. Let's see the example:

  for (var x = 0; x < 10; x++) {
    console.log(x);
    var Log = app.models.Log;
    Log.findOrCreate({
      where: {
        modelName: '123'
      }
    }, {
      modelName: '123'
    }, function(err, log) {
      if (err) return;
      if (log) {
        console.log("+ " + log.id);
      }
    });
  }

I think it should create 1 record with modelName '123' only, but I got 10 finally.

Is there something wrong?

Answer 1

That's expected. You are running the code synchronously. If you run it in an asynchronous way, you will see only one document being created. Try this:

var arr = new Array(10);
async.eachSeries(arr, function (pos, callback) {
    console.log(pos);
    Log.findOrCreate({
      where: {
        txt: '123'
      }
    }, {
      txt: '123'
    }, function (err, log) {
      if (err) return;
      console.log("+ " + log.id);
      callback();
    });
  }, function (err) {
    if (err) {
      throw err;
    }
  }
);