Multiple Queries Parse Javascript

Question

I have been developing a mock up android app and want to write Parse Background job. My Parse users are customers and I sell services that customers can subscribe to. The _User class is for customers and the CustomerSubscriptions class is for subscriptions. I'm trying to update all the customers' bills but I can't.

Can some one steer me in the right direction?

Thanks

     Parse.Cloud.job("billCustomers", function(request, response) {

  Parse.Cloud.useMasterKey(); 
  var query = new Parse.Query(CustomerSubscriptions);
  var array = new Array();
  //For each registered user
  query.find().then(function(results) {
    for (var i = 0; i < results.length; ++i) {
      var username = results[i].get("username");
      array[username] = results[i].get("Price");
    }

    var query2 = new Parse.Query(Parse.User);

    return query2.find();
  }).then(function(results) {
    for (var i = 0; i < results.length; ++i) {
      var username = results[i].get("username");
      results[i].set("Bill",array[username]);
      results[i].save();

    }
  }, function(error) {
    response.error("Error");
  });

  });

toddg · Accepted Answer · 2015-02-25T02:36:48.643

1

The problem is in results[i].save(); That is an async operation. Your function is most likely returning before all of the saves are complete. I would collect all of your promises in an array and then use Parse.Promise.when to return once they are all complete. You'll also want to call response.success() when you're done.

Try something like this:

.then(function(results) {

  var savePromises = [];  // this will collect save promises 
  _.each(results, function(result) { // or a for loop, if you don't use underscore

    var username = result.get("username");
    result.set("Bill",array[username]);
    savePromises.push(result.save());
  });

  // now do the saves
  return Parse.Promise.when(savePromises);
}, function(error) {
  response.error();
}).then(function() {
   // this should execute once all the saves are done
   // Set the job's success status
   response.success("saves completed");
});

I'm using underscore to iterate through the results array.

edited Feb 25 '15 at 02:36

answered Feb 25 '15 at 02:28

toddg

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Good answer. Appropriately adapted from http://stackoverflow.com/questions/27723121/parse-javascript-sdk-and-promise-chaining – danh Feb 25 '15 at 03:20
Thanks so much @Todd/@dahn. I wish I had a debugger for this. Unfortunately it still doesn't work.Am I initializing the array correctly? – abe Feb 25 '15 at 03:28
1

Are you getting any output from the parse console? Also, not sure why you're indexing into your array with `username` but I don't think js supports associative arrays. http://www.w3schools.com/js/js_arrays.asp – toddg Feb 25 '15 at 13:06
Thanks! The array was the final problem. Olive Juice – abe Feb 25 '15 at 19:08
Oh wait. I want to run one final query. query3. Can I return query3 where `Parse.Promise.when(savePromises)` is and just call `Parse.Promise.when(savePromises)` before the retun statement? – abe Feb 25 '15 at 19:14
1

Depending on what you want to do with query3, I would just put it where response.success() is, like `return query3.find()` and add in one final promise chain to call response.success() once query3.find completes. – toddg Feb 25 '15 at 20:37

Multiple Queries Parse Javascript

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