ui-charts: fix useManchetteWithSpaceTimeChart() errors with zero waypoints

In multiple spots the hook assumed there is at least one waypoint in
list. Add guards to avoid crashing with errors when that's the case.

Signed-off-by: Simon Ser <[email protected]>

Author: emersion

front/ui/ui-charts/src/manchette/hooks/useManchetteWithSpaceTimeChart.tsx

@@ -366,6 +366,7 @@ const useManchetteWithSpaceTimeChart = ({
     // Constant scale:
     if (isProportional) {
       const baseScale = baseScales[0];
+      if (!baseScale) return baseScales;
       const coefficient: number =
         'coefficient' in baseScale && typeof baseScale.coefficient === 'number'
           ? baseScale.coefficient
@@ -445,10 +446,13 @@ const useManchetteWithSpaceTimeChart = ({
   const { manchetteContents, manchetteHeight } = useMemo(() => {
     const spaceScaleTree = spaceScalesToBinaryTree(spaceOrigin, spaceScales);
     const getSpacePixel = getSpaceToPixel(0, spaceScaleTree);
-    const totalManchetteHeight = Math.max(
-      getSpacePixel(spaceScales.at(-1)!.to, true) + BASE_WAYPOINT_HEIGHT,
-      height - FOOTER_HEIGHT
-    );
+    let totalManchetteHeight = height - FOOTER_HEIGHT;
+    if (spaceScales.length > 0) {
+      totalManchetteHeight = Math.max(
+        totalManchetteHeight,
+        getSpacePixel(spaceScales.at(-1)!.to, true) + BASE_WAYPOINT_HEIGHT,
+      );
+    }
 
     if (!splitPoints)
       return {

front/ui/ui-charts/src/manchette/utils/index.ts

@@ -7,8 +7,12 @@ export const positionMmToKm = (position: number) => Math.round((position / 10000
 
 export const msToS = (time: number) => time / 1000;
 
-export const calcTotalDistance = <T extends { position: number }>(ops: T[]) =>
-  ops.at(-1)!.position - ops.at(0)!.position;
+export const calcTotalDistance = <T extends { position: number }>(ops: T[]) => {
+  if (ops.length === 0) {
+    return 0;
+  }
+  return ops.at(-1)!.position - ops.at(0)!.position;
+};
 
 type Point = {
   x: number;