Clarify the mutation

react-dnd · Oct 12, 2015 · 559f8ff · 559f8ff
1 parent 0af7de9
commit 559f8ff
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/examples/04 Sortable/Simple/Card.js b/examples/04 Sortable/Simple/Card.js
@@ -58,7 +58,10 @@ const cardTarget = {
  // Time to actually perform the action
  props.moveCard(dragIndex, hoverIndex);
 
- // Update the monitors item with the new index
+ // Note: we're mutating the monitor item here!
+ // Generally it's better to avoid mutations,
+ // but it's good here for the sake of performance
+ // to avoid expensive index searches.
  monitor.getItem().index = hoverIndex;
  }
 };