Ranking: Enhance performance with many items

[mikeamelin]

~ 200 items.
Drag-n-drop is too slow.

Screen.Recording.2024-04-12.at.11.44.56.mov

[mikeamelin]

Looks like the issue is still here.

[tsv2013]

The issue is in survey-knockoutui only - in drag drop helper:

  protected afterDragOver(dropTargetNode: HTMLElement): void {
    const choices = this.parentElement.rankingChoices;
    const dropTargetIndex = choices.indexOf(this.dropTarget);
    const draggedElementIndex = choices.indexOf(this.draggedElement);

    choices.splice(draggedElementIndex, 1);
    choices.splice(dropTargetIndex, 0, this.draggedElement);
    this.parentElement.setPropertyValue("rankingChoices", choices); // <- Here we assign all the question that triggers whole list re-rendering in KO

We decided not to fis it and use react version on our site. Probably get rid of KO support in v2.0 and use react+preact instead.