using underscore's “difference” method on arrays of objects

Question

_.difference([], []) 

this method works fine when i'm having primitive type data like

var a = [1,2,3,4]; var b = [2,5,6]; 

and the _.difference(a,b) call returns [1,3,4]

but in case i'm using object like

var a = [{'id':1, 'value':10}, {'id':2, 'value':20}]; var b = [{'id':1, 'value':10}, {'id':4, 'value':40}]; 

doesn't seem to work

Answer 1

try this on for size for finding the difference of an array of objects:

var test = [{a: 1},{b: 2}]; var test2 = [{a: 1}];  _.filter(test, function(obj){ return !_.findWhere(test2, obj); });