refactor(sign): cleaner divider code in PDVview

src/components/PDFView/index.tsx

@@ -45,18 +45,17 @@ const PdfView = ({
   const filterMarksByFile = (marks: Mark[], hash: string): Mark[] => {
     return marks.filter((mark) => mark.pdfFileHash === hash)
   }
-  const isNotLastPdfFile = (index: number, files: CurrentUserFile[]): boolean =>
-    index !== files.length - 1
   return (
     <div className="files-wrapper">
       {files.length > 0 ? (
-        files.map((currentUserFile, index, arr) => {
+        files
+          .map<React.ReactNode>((currentUserFile) => {
             const { hash, file, id } = currentUserFile
 
             if (!hash) return
             return (
-            <React.Fragment key={index}>
               <div
+                key={`file-${file.name}`}
                 id={file.name}
                 className="file-wrapper"
                 ref={(el) => (pdfRefs.current[id] = el)}
@@ -70,10 +69,13 @@ const PdfView = ({
                   otherUserMarks={filterMarksByFile(otherUserMarks, hash)}
                 />
               </div>
-              {isNotLastPdfFile(index, arr) && <FileDivider />}
-            </React.Fragment>
             )
           })
+          .reduce((prev, curr, i) => [
+            prev,
+            <FileDivider key={`separator-${i}`} />,
+            curr
+          ])
       ) : (
         <LoadingSpinner variant="small" />
       )}