index.js
function(b) {
        if (b instanceof Model) {
          if (this.constructor !== b.constructor) return false;
          b = b.attributes;
        }
        return _.isEqual(this.attributes, b);
      }
function(b) {
        if (b instanceof Model) {
          if (this.constructor !== b.constructor) return false;
          b = b.attributes;
        }
        return _.isEqual(this.attributes, b);
      }
function ( b ) { if ( b instanceof Model ) { if ( this . constructor !== b . constructor ) return false ; b = b . attributes ; } return _ . isEqual ( this . attributes , b ) ; }
Custom Underscore equality method.
Custom Underscore equality method .