Storing the GPX export (#9) in Download directory and checking if the file allready exiss.

src/components/map/GpxExport.tsx

@@ -14,24 +14,54 @@ const GpxExport: React.FC<{ gpx: any }> = (props: { gpx: any }) => {
 
   const hiddenLinkElement = useRef<HTMLAnchorElement>(null);
 
-  var downloadName: string;
+  var downloadBaseName: string;
 
   if (props.gpx.metadata.name !== undefined) {
-    downloadName = props.gpx.metadata.name;
+    downloadBaseName = props.gpx.metadata.name.substr(
+      0,
+      props.gpx.metadata.name.lastIndexOf('.')
+    );
   } else if (props.gpx.gpx.metadata.name !== undefined) {
-    downloadName = `${props.gpx.gpx.metadata.name}.gpx`;
+    downloadBaseName = props.gpx.gpx.metadata.name;
   } else {
-    downloadName = `track-${props.gpx.metadata.lastModified}.gpx`;
+    downloadBaseName = `track-${props.gpx.metadata.lastModified}`;
   }
 
+  const downloadExt = 'gpx';
+
+  const downloadName = `${downloadBaseName}.${downloadExt}`;
+
+  const getNewFilename: any = async (
+    filename: string,
+    extension: string,
+    i = 0
+  ) => {
+    const filenameToTest =
+      i === 0 ? `${filename}.${extension}` : `${filename}(${i}).${extension}`;
+    try {
+      const statResult = await Filesystem.stat({
+        path: filenameToTest,
+        directory: Directory.Documents,
+      });
+      return getNewFilename(filename, extension, i + 1);
+    } catch {
+      return filenameToTest;
+    }
+  };
+
   const download = async (event: any) => {
     event.preventDefault();
     console.log('download()');
     const gpxAsXml = await getGpxAsXmlString(db, props.gpx._id);
     console.log(`gpxAsXml: ${gpxAsXml}`);
     if (isCapacitor) {
+      const filename = await getNewFilename(
+        `../Download/${downloadBaseName}`,
+        downloadExt
+      );
+      console.log(`filename: ${filename}`);
       const fileUrl = await Filesystem.writeFile({
-        path: `Download/${downloadName}`,
+        path: filename,
         data: gpxAsXml,
         directory: Directory.Documents,
         encoding: Encoding.UTF8,