underscore playground
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore.js"></script>
<div id="content">
</div>
JavaScript
var test = [{
a: 1
}, {
b: 2
}];
var test2 = [{
a: 1
}];
var diff = _.filter(test, function(obj) {
return !_.findWhere(test2, obj);
});
console.log(diff)