fix type error

Author: ylked

via-ui/src/components/SwissMap.vue

@@ -141,8 +141,8 @@ watch(
   () => {
     const s = gameState.value.shapePreview
     if (s.length === 0) return ''
-    const a = s[0]
-    const b = s[s.length - 1]
+    const a = s[0]!!
+    const b = s[s.length - 1]!!
     return `${s.length}:${a.lat},${a.lon}:${b.lat},${b.lon}`
   },
   () => {