Added Pdf File wrapper. migrated merge to use it

shared-operations/functions/mergePDFs.ts

@@ -1,16 +1,20 @@
 
 import { PDFDocument } from 'pdf-lib';
+import { PdfFile, convertAllToLibPdf, fromPDFDocument } from '../wrappers/PdfFile';
 
-export async function mergePDFs(snapshots: (string | Uint8Array | ArrayBuffer)[]): Promise<Uint8Array> {
+export async function mergePDFs(files: PdfFile[]): Promise<PdfFile> {
+
+    await convertAllToLibPdf(files);
 
     const mergedPdf = await PDFDocument.create(); 
 
-    for (let i = 0; i < snapshots.length; i++) {
-        const pdfToMerge = await PDFDocument.load(snapshots[i]);
+    for (let i = 0; i < files.length; i++) {
+        const pdfToMerge = files[i].pdfLib;
+        if (!pdfToMerge) continue;
 
         const copiedPages = await mergedPdf.copyPages(pdfToMerge, pdfToMerge.getPageIndices());
         copiedPages.forEach((page) => mergedPdf.addPage(page));
     }
 
-    return mergedPdf.save();
+    return fromPDFDocument(mergedPdf);
 };

shared-operations/wrappers/PdfFile.ts

@@ -0,0 +1,56 @@
+
+import { PDFDocument } from 'pdf-lib';
+
+export class PdfFile {
+    byteArray: Uint8Array | null;
+    pdfLib: PDFDocument | null;
+    filename?: string;
+
+    constructor() {    
+        this.byteArray = null;
+        this.pdfLib = null;
+    }   
+
+    async convertToByteArray(): Promise<void> {
+        if (this.pdfLib) {
+            this.byteArray = await this.pdfLib.save();
+            this.pdfLib = null;
+        }
+    }
+    async convertToLibPdf(): Promise<void> {
+        if (this.byteArray) {
+            this.pdfLib = await PDFDocument.load(this.byteArray, {
+                updateMetadata: false,
+            });
+            this.byteArray = null;
+        }
+    }
+}
+
+export function fromMulterFile(value: Express.Multer.File, filename?: string) {
+    return fromUint8Array(value.buffer, filename)
+}
+export function fromUint8Array(value: Uint8Array, filename?: string) {
+    const out = new PdfFile();
+    out.byteArray = value;
+    out.filename = filename;
+    return out;
+}
+export function fromPDFDocument(value: PDFDocument, filename?: string) {
+    const out = new PdfFile();
+    out.pdfLib = value;
+    out.filename = filename;
+    return out;
+}
+
+export async function convertAllToByteArray(files: PdfFile[]): Promise<void> {
+    const pdfPromises = files.map(s => s.convertToByteArray());
+    await Promise.all(pdfPromises);
+
+}
+
+export async function convertAllToLibPdf(files: PdfFile[]): Promise<void> {
+    const pdfPromises = files.map(s => s.convertToLibPdf());
+    await Promise.all(pdfPromises);
+
+}