Loop isn't being called in a promise - Javascript NodeJS

Asked Aug 13 '17 at 06:53

Active Aug 13 '17 at 11:01

Viewed 70 times

I have this code :

  console.log("before querying");


  var x = collection.findOne(query)
    .then(function (retrievedData) {

     console.log("after querying");

     for (var i = 0; i < myArray.length || function() {

      console.log("looks like the loop is complete");
      return "";

      }(), false; i++)
        {
         console.log("entering loop...");
        }
    }

When I run this code, I see

before querying

Then the code crashes complaining that the function containing this code has not returned anything.

The actual error is this :

TypeError: Cannot read property 'then' of undefined

As you can see, I can't even see after querying. The code is running future steps before completing the .then part of findOne. I haven't posted all of the code since it's long and a bit complex. Could you tell me what I am doing wrong? Thank in advance.

edited Aug 13 '17 at 11:01

asked Aug 13 '17 at 06:53

jason

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What is the collection variable? – Malice Aug 13 '17 at 07:04
@Malice It's a MongoDB collection. I'm using native MongoDB driver. – jason Aug 13 '17 at 07:04
1

what find one returns ? and what is myArray ? – Basil Battikhi Aug 13 '17 at 07:05
https://docs.mongodb.com/manual/reference/method/db.collection.findOne/ – Malice Aug 13 '17 at 07:06
I dont't think findOne returns a promise as you intended... – Malice Aug 13 '17 at 07:06
1

Possible duplicate of [Does mongoose findOne on model return a promise?](https://stackoverflow.com/questions/35662210/does-mongoose-findone-on-model-return-a-promise) – Evan Trimboli Aug 13 '17 at 07:15
@Malice I think the code was working before I was adding that loop. I surely remember the query results inside the `.then` part. – jason Aug 13 '17 at 07:16
@EvanTrimboli My question is not related with Mongoose at all. – jason Aug 13 '17 at 07:17
Is the `, false` intended ? – Malice Aug 13 '17 at 07:19
@Malice Yes, I saw it here : https://stackoverflow.com/a/5602834/1954132 – jason Aug 13 '17 at 07:20
I'm 100% sure that findOne returns promise. – jason Aug 13 '17 at 07:42
"Then the code crashes complaining that the function containing this code has not returned anything." Post the actual error. – Evan Trimboli Aug 13 '17 at 10:57
@EvanTrimboli I posted. Thanks. – jason Aug 13 '17 at 11:01
1

Exactly what it says then, `findOne` is returning undefined. I suggest you post a real test case. – Evan Trimboli Aug 13 '17 at 11:08
can you try doing this ? `var retrievedData = collection.findOne(query);` and print what you're getting ? – Malice Aug 13 '17 at 12:03
@Malice I'm getting a promise... Why am I getting a promise? Shouldn't I get a cursor? – jason Aug 13 '17 at 16:10
Are you using bluebird or some promise library ? – Malice Aug 13 '17 at 18:33

Loop isn't being called in a promise - Javascript NodeJS

0 Answers0