swipeTracker: Simplify finding previous point

We have findLastIndex() nowadays to search an array in reverse
direction.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3967>
(cherry picked from commit 8e29babca8adc677fcd5bc8457f497dd849ae884)

diff --git a/js/ui/swipeTracker.js b/js/ui/swipeTracker.js
index 82edef29eaa83e9ef7e7c7707765eefcdae4de59..18f6657db18b39d56488b5bab97e3e51e6b9d51d 100644 (file)
--- a/js/ui/swipeTracker.js
+++ b/js/ui/swipeTracker.js
@@ -523,8 +523,7 @@ export const SwipeTracker = GObject.registerClass({
     }
 
     _findPreviousPoint(pos) {
-        const reversedIndex = this._snapPoints.slice().reverse().findIndex(p => p <= pos);
-        return this._snapPoints.length - 1 - reversedIndex;
+        return this._snapPoints.findLastIndex(p => p <= pos);
     }
 
     _findPointForProjection(pos, velocity) {