Parse.com背景作业云代码无法调用未定义的方法'then'

Question

I am new to cloudcode and javascript so promise concepts are still not clear, I am trying to upload read a level file and saving it to the Class Levels using background job but in below code I am getting error Cannot call method 'then' of undefined

I am not sure whats going wrong ? and it is very difficult to debug when your concepts are not clear s it should be, so it would be great help if some one can clear my concepts of Parse promises and also help with the above error in this code.

Parse.Cloud.job("uploadLevelJob" , function(request , status){
    var Levels= Parse.Object.extend("Levels");
    var levels= request.params.arrayOfLevels;
    var promise = new Parse.Promise.as();
    _.each(levels , function(level){
        promise = promise.then(function() {
            var tempObj = new Levels();
            tempObj.set("levelId",parseInt(level[i][0]));
            tempObj.set("levelName",level[i][1]);
            return result.save();          
        });
        return promise;
    }).then(function(){
        status.success("Uploaded ! ");  
    });

});

Answer 1

It seems you are trying to use promises in series, but you can actually use parallel promises in your case. Because each save is independent from each other. By the way i and result seem to be undefined in your code. I assume the levels is an array like [[levelId, "levelName"], ...]

var Levels = Parse.Object.extend("Levels");

Parse.Cloud.job("uploadLevelJob" , function(request , status){
  var levels = request.params.arrayOfLevels;

  var promises = [];
  _.each(levels , function(level) {
    var tempObj = new Levels();
    tempObj.set("levelId",parseInt(level[0]));
    tempObj.set("levelName",level[1]);
    promises.push(tempObj.save());
  });

  return Parse.Promise.when(promises).then(function() {
    status.success("Migration completed successfully.");
  }, function(error) {
    status.error("Uh oh, something went wrong.");
  });

});