Nest linked JavaScript objects

More than once in my coding career, I've come across impractical data structures that need transformation. One particularly annoying one was a flat array of objects that needed to be linked to one another. To make it easier to work with, I needed to nest them in a tree-like structure.

From the get-go, I knew that recursion was the way to go. Using Array.prototype.filter() and Array.prototype.map(), I was able to filter the items based on their id and map them to a new object that had a children property. This property recursively nested the items based on which ones were children of the current item.

In order to customize my solution, I added two optional arguments: id and link. The former defaults to null, indicating that the object is not linked to another one. The latter defaults to 'parentId', which is the property that links the object to another one by its id.

const nest = (items, id = null, link = 'parentId') =>
  items
    .filter(item => item[link] === id)
    .map(item => ({ ...item, children: nest(items, item.id, link) }));

const comments = [
  { id: 1, parentId: null },
  { id: 2, parentId: 1 },
  { id: 3, parentId: 1 },
  { id: 4, parentId: 2 },
  { id: 5, parentId: 4 }
];
const nestedComments = nest(comments);
/*
[
  {
    id: 1,
    parentId: null,
    children: [
      {
        id: 2,
        parentId: 1,
        children: [
          {
            id: 4,
            parentId: 2,
            children: [
              {
                id: 5,
                parentId: 4,
                children: []
              }
            ]
          }
        ]
      },
      {
        id: 3,
        parentId: 1,
        children: []
      }
    ]
  }
]
*/