I have an array of objects as shown below:

[

{ pallet: 987, lpn: 1234, city: "London", country: "UK" },

{ pallet: 987, lpn: 5634, city: "London", country: "UK" },

{ pallet: null, lpn: 4933, city: "London", country: "UK" },

{ pallet: 757, lpn: 9264, city: "London", country: "UK" }

]

Expected Behavior:

If the pallet field has a value, the records should be grouped by pallet.

If the pallet field is null, that record should be displayed as a separate, independent row, not part of any group.

Expected Output Structure:

Pallet 987

├─ LPN 1234

└─ LPN 5634

LPN 4933

Pallet 757

└─ LPN 9264