Takes a jQuery object of checkbox elements and returns info about the checked ones

readCheckboxes.js

// Takes a jQuery object of checkbox elements and returns:
// - An array of the IDs of the checked ones
// - (if asCollection is true) A collection of the checked ones where key=ID, value=true
// Dependency: jQuery, underscore/lodash
function readCheckboxes($cb, asCollection) {
  return _($cb.filter(":checked"))
    .map(function(item) {
      return item.id;
    })
    .thru(function(item) {
      return (!!asCollection ? _(item).zipObject().mapValues(function() {
        return true;
      }).value() : item);
    })
    .value();
}

btw I really love the functional style where the body of a function is only a return statement.