Javascript – How to properly replace value of an object in an array and sort it by that value

I want to change priority of a draggedItem with a priority of a targetItem.

If they are the same, they should be updated correctly (draggedItem should get priority of targetItem and targetItem priority should be increased by one, because it is the same as priority of draggedItem).

The priority of all other items should also be updated correctly (based on new draggedItem and targetItem priority) and in the end result I should have an array of objects where all objects have different priority.

Thus, I have a function as follows:

const updatePriorities = (data, draggedItem, targetItem) => {
  const draggedItemPriority = draggedItem?.priority;
  const targetItemPriority = targetItem?.priority;

  if (draggedItemPriority === undefined || targetItemPriority === undefined || draggedItemPriority === null || targetItemPriority === null) {
    return data;
  }

  const minPriority = Math.min(draggedItemPriority, targetItemPriority);
  const maxPriority = Math.max(draggedItemPriority, targetItemPriority);

  const newData = map(data, (item) => {
    if (item.priority === draggedItemPriority) {
      return { ...item, priority: targetItemPriority };
    } else if (item.priority >= minPriority && item.priority <= maxPriority) {
      const priorityOffset = targetItemPriority < draggedItemPriority ? 1 : -1;
      return { ...item, priority: item.priority + priorityOffset };
    } 
    return item;
  });

  return orderBy(newData, 'priority');
};

Thus if all objects in the array have different priority, it works fine. Thus with data as follows:

const mockedData = [
  { name: 'Item 0', priority: 0 },
  { name: 'Item 1', priority: 1 },
  { name: 'Item 2', priority: 2 },
  { name: 'Item 3', priority: 3 },
  { name: 'Item 4', priority: 4 },
  { name: 'Item 5', priority: 5 }
];
const mockedDraggedItem1 = mockedData[2];
const mockedTargetItem1 = mockedData[1];
const result = updatePriorities(mockedData, mockedDraggedItem1, mockedTargetItem1)
// The result
[
  { name: 'Item 0', priority: 0 },
  { name: 'Item 2', priority: 1 },
  { name: 'Item 1', priority: 2 },
  { name: 'Item 3', priority: 3 },
  { name: 'Item 4', priority: 4 },
  { name: 'Item 5', priority: 5 }
];

I get correct result, the priority is updated correctly and Item 2 came to second place (got priority 1) and Item 1 went to third place (got priority 2). That is all fine.

But when I have two objects with the same priority in the array. For example:

const mockedData = [
  { name: 'Item 0', priority: 0 },
  { name: 'Item 1', priority: 1 },
  { name: 'Item 2', priority: 1 },
  { name: 'Item 3', priority: 3 },
  { name: 'Item 4', priority: 4 },
  { name: 'Item 5', priority: 5 }
];
const mockedDraggedItem1 = mockedData[2];
const mockedTargetItem1 = mockedData[1];

Then it does not work as expected, want the priority of draggedItem and targetItem is not updated.

I should get next result:

[
  { name: 'Item 0', priority: 0 },
  { name: 'Item 2', priority: 1 },
  { name: 'Item 1', priority: 2 },
  { name: 'Item 3', priority: 3 },
  { name: 'Item 4', priority: 4 },
  { name: 'Item 5', priority: 5 }
];

What should I do to update it correctly?

Thanks in advance.