Merge objects with same id in array

I guess I have a dead simple problem but still didn't find a solution. I have an array which looks like this:

var originalArray = [{
  id: 1,
  elements: [1, 2]
},
{
  id: 1,
  elements: [3, 4]
},
{
  id: 5,
  elements: ['a', 'b']
},
{
  id: 5,
  elements: ['c', 'd']
}, {
  id: 27,
  elements: []
}]

I'd like to modify it to look like this (merge by id and join elements):

newArray = [{
  id: 1,
  elements: [1, 2, 3, 4]
}, {
  id: 5,
  elements: ['a', 'b', 'c', 'd']
}, {
  id: 27,
  elements: []
}]

I already had multiple tries but still didn't find an elegant way of doing it.