cool lodash code

checkboxToggling.js

/* checks to see if item id arrangement in packages has changed */
let compareItemIds = (oldIds, newIds) => {
  return _.difference(newIds, oldIds).concat(_.difference(oldIds, newIds));
};

/* gets the item of ids of current packages and orignal packages
   and compares them for changes */
let haveItemsChanged = () => {

  let curIds = [];
  let oldIds = [];
  let currentPackages = $scope.packages;
  let orginalPackages = $scope.orginalPackages;

  return _.filter(orginalPackages, (pkg, index) => {
    _.each(pkg.package_items, (item) => {
      oldIds.push(_.pick(item, 'id').id);
    });
    _.each(currentPackages[index].package_items, (item) => {
      curIds.push(_.pick(item, 'id').id);
    });
    return [].concat(compareItemIds(oldIds, curIds)).length > 0;
  }).length > 0;

};

/* updates items on drop if item different than
   initial drag item, resets selected to true */
$scope.onDrop = () => {
  $scope.itemsSwapped = haveItemsChanged();
  if ($scope.itemsSwapped) {
    $scope.reset(); // make sure all packages are selected on swap
  }
};