fix: map layer update error

frontend/src/components/MapComponent.vue

@@ -152,28 +152,31 @@ export default {
         };
 
         const updateSamplesLayer = () => {
-            map.value.removeLayer('samples-layer');
-
-            map.value.addLayer({
-                    'id': 'samples-layer',
-                    'source': 'samples',
-                    'source-layer': 'public.geodata',
-                    'type': 'circle',
-                    'paint': {
-                        'circle-stroke-width': 1,
-                        'circle-stroke-color': '#FFFFFF',
-                        'circle-color': [
-                            'case',
-                            ['boolean', ['feature-state', 'beenClicked'], false],
-                            '#ffff00',
-                            '#1a9641'
-                        ],
-                        'circle-opacity': 0.8,
-                        'circle-radius': 16
-                    },
-                    filter: ["match", ["get", "internal_id"], props.idlist, true, false]
-                });
-
+            if (map.value.getLayer('samples-layer')){
+                map.value.removeLayer('samples-layer');
+            }
+            
+            if(props.idlist.length){
+                map.value.addLayer({
+                        'id': 'samples-layer',
+                        'source': 'samples',
+                        'source-layer': 'public.geodata',
+                        'type': 'circle',
+                        'paint': {
+                            'circle-stroke-width': 1,
+                            'circle-stroke-color': '#FFFFFF',
+                            'circle-color': [
+                                'case',
+                                ['boolean', ['feature-state', 'beenClicked'], false],
+                                '#ffff00',
+                                '#1a9641'
+                            ],
+                            'circle-opacity': 0.8,
+                            'circle-radius': 16
+                        },
+                        filter: ["match", ["get", "internal_id"], props.idlist, true, false]
+                    });
+            }
         };
 
         onMounted(() => {