Question

How can i compare two collections in backbone?

I have two collection 1C contains 1,2,3 while 2C contains 2,4,5 What i want to do is to remove 2 from 2C because 1C already has a value of 2 after that normally render the collection.

I tried this

this.1C.each(function(model1){
  this.2C.each(function(model2){
     if(model1 === model2){
        2C.remove(model2);
     }
  });
});

But it doesnt work. Any ideas?

Answer 1

I would hazard a guess that model1 and model2 are never the same instance of a model and therefore never match. Have you tried comparing model ID’s or similar? eg. model1.id == model2.id

maybe add some debugging so you can see what’s happening..

this.1C.each(function(model1){
  console.log('m1:'+model1.categoryCode);
  this.2C.each(function(model2){
     console.log('  m2:'+model2.categoryCode);
     if(model1.categoryCode == model2.categoryCode){
        console.log('removing m2:'+model2.categoryCode);
        2C.remove(model2);
     }
  });
});