Favorite folders (#7998)

closes - #5755

---------

Co-authored-by: martmull <martmull@hotmail.fr>
Co-authored-by: Lucas Bordeau <bordeau.lucas@gmail.com>
Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-front/src/modules/favorites/utils/calculateNewPosition.ts

@@ -0,0 +1,33 @@
+type CalculateNewPositionParams = {
+  destinationIndex: number;
+  sourceIndex: number;
+  items: Array<{ position: number }>;
+};
+
+export const calculateNewPosition = ({
+  destinationIndex,
+  sourceIndex,
+  items,
+}: CalculateNewPositionParams): number => {
+  if (destinationIndex === 0) {
+    return items[0].position / 2;
+  }
+
+  if (destinationIndex === items.length - 1) {
+    return items[destinationIndex - 1].position + 1;
+  }
+
+  if (destinationIndex > sourceIndex) {
+    return (
+      (items[destinationIndex + 1].position +
+        items[destinationIndex].position) /
+      2
+    );
+  }
+
+  return (
+    items[destinationIndex].position -
+    (items[destinationIndex].position - items[destinationIndex - 1].position) /
+      2
+  );
+};