code: function extendPreventingOverrides (a, b) {
            Object.keys(b).forEach(addContentFromBtoA)
            return a
  
            function addContentFromBtoA (key) {
              if (a.hasOwnProperty(key)) {
                mergeIntoAnArray(a, b, key)
              } else {
                a[key] = b[key]
              }
            }
          }
docs: for checkboxes we want to obtain all selected values in an array