added 2 new root folders

shared-operations/functions/editMetadata.js

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+/**
+ * @typedef {Object} Metadata
+ * @property {string | null | undefined} Title - The title of the document.
+ * @property {string | null | undefined} Author - The author of the document.
+ * @property {string | null | undefined} Subject - The subject of the document.
+ * @property {string[] | null | undefined} Keywords - An array of keywords associated with the document.
+ * @property {string | null | undefined} Producer - The producer of the document.
+ * @property {string | null | undefined} Creator - The creator of the document.
+ * @property {Date | null | undefined} CreationDate - The date when the document was created.
+ * @property {Date | null | undefined} ModificationDate - The date when the document was last modified.
+ */
+
+/**
+ * 
+ * @param {Uint16Array} snapshot
+ * @param {Metadata} metadata - Set property to null or "" to clear, undefined properties will be skipped.
+ * @param {import('pdf-lib')} PDFLib
+ * @returns 
+ */
+export async function editMetadata(snapshot, metadata, PDFLib) {
+    // Load the original PDF file
+    const pdfDoc = await PDFLib.PDFDocument.load(snapshot, {
+        parseSpeed: PDFLib.ParseSpeeds.Fastest,
+    });
+
+    if(metadata.Title !== undefined)
+        pdfDoc.setTitle(metadata.Title);
+
+    if(metadata.Author !== undefined)
+        pdfDoc.setAuthor(metadata.Author)
+
+    if(metadata.Subject !== undefined)
+        pdfDoc.setSubject(metadata.Subject)
+    
+    if(metadata.Keywords !== undefined)
+        pdfDoc.setKeywords(metadata.Keywords)
+    
+    if(metadata.Producer !== undefined)
+        pdfDoc.setProducer(metadata.Producer)
+
+    if(metadata.Creator !== undefined)
+        pdfDoc.setCreator(metadata.Creator)
+
+    if(metadata.CreationDate !== undefined)
+        pdfDoc.setCreationDate(metadata.CreationDate)
+
+    if(metadata.ModificationDate !== undefined)
+        pdfDoc.setModificationDate(metadata.ModificationDate)
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};

shared-operations/functions/extractPages.js

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+export async function extractPages(snapshot, pagesToExtractArray, PDFLib) {
+    const pdfDoc = await PDFLib.PDFDocument.load(snapshot)
+
+    // TODO: invent a better format for pagesToExtractArray and convert it.
+    return createSubDocument(pdfDoc, pagesToExtractArray, PDFLib);
+};
+
+export async function createSubDocument(pdfDoc, pagesToExtractArray, PDFLib) {
+    const subDocument = await PDFLib.PDFDocument.create();
+
+    // Check that array max number is not larger pdf pages number
+    if(Math.max(...pagesToExtractArray) >= pdfDoc.getPageCount()) {
+        throw new Error(`The PDF document only has ${pdfDoc.getPageCount()} pages and you tried to extract page ${Math.max(...pagesToExtractArray)}`);
+    }
+
+    const copiedPages = await subDocument.copyPages(pdfDoc, pagesToExtractArray);
+
+    for (let i = 0; i < copiedPages.length; i++) {
+        subDocument.addPage(copiedPages[i]);
+    }
+
+    return subDocument.save();
+}

shared-operations/functions/impose.js

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+export async function impose(snapshot, nup, format, pdfcpuWrapper) {
+    return await pdfcpuWrapper.oneToOne([
+            "pdfcpu.wasm",
+            "nup",
+            "-c",
+            "disable",
+            'f:' + format,
+            "/output.pdf",
+            String(nup),
+            "input.pdf",
+        ], snapshot);
+}

shared-operations/functions/mergePDFs.js

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+export const mergePDFs = async (snapshots, PDFLib) => {
+
+    const mergedPdf = await PDFLib.PDFDocument.create(); 
+
+    for (let i = 0; i < snapshots.length; i++) {
+        const pdfToMerge = await PDFLib.PDFDocument.load(snapshots[i]);
+
+        const copiedPages = await mergedPdf.copyPages(pdfToMerge, pdfToMerge.getPageIndices());
+        copiedPages.forEach((page) => mergedPdf.addPage(page));
+    }
+
+    return mergedPdf.save();
+};

shared-operations/functions/rotatePages.js

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+export async function rotatePages (snapshot, rotation, PDFLib) {
+    // Load the original PDF file
+    const pdfDoc = await PDFLib.PDFDocument.load(snapshot, {
+        parseSpeed: PDFLib.ParseSpeeds.Fastest,
+    });
+
+    const pages = pdfDoc.getPages();
+
+    pages.forEach(page => {
+        // Change page size
+        page.setRotation(PDFLib.degrees(rotation))
+    });
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};

shared-operations/functions/scaleContent.js

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+export async function scaleContent(snapshot, scaleFactor, PDFLib) {
+    // Load the original PDF file
+    const pdfDoc = await PDFLib.PDFDocument.load(snapshot, {
+        parseSpeed: PDFLib.ParseSpeeds.Fastest,
+    });
+
+    const pages = pdfDoc.getPages();
+
+    pages.forEach(page => {
+        const width = page.getWidth();
+        const height = page.getHeight();
+        
+        // Scale content
+        page.scaleContent(scaleFactor, scaleFactor);
+        const scaled_diff = {
+            width: Math.round(width - scaleFactor * width),
+            height: Math.round(height - scaleFactor * height),
+        };
+
+        // Center content in new page format
+        page.translateContent(Math.round(scaled_diff.width / 2), Math.round(scaled_diff.height / 2));
+
+    });
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};

shared-operations/functions/scalePage.js

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+export async function scalePage(snapshot, pageSize, PDFLib) {
+    // Load the original PDF file
+    const pdfDoc = await PDFLib.PDFDocument.load(snapshot, {
+        parseSpeed: PDFLib.ParseSpeeds.Fastest,
+    });
+
+    const new_size = pageSize;
+
+    const pages = pdfDoc.getPages();
+
+    pages.forEach(page => {
+        // Change page size
+        page.setSize(new_size.width, new_size.height);
+    });
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};
+
+export const PageSize = {
+    a4: {
+        width: 594.96,
+        height: 841.92
+    },
+    letter: {
+        width: 612,
+        height: 792
+    }
+};

shared-operations/functions/splitPDF.js

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+import { createSubDocument } from "./extractPages.js";
+
+export async function splitPDF(snapshot, splitAfterPageArray, PDFLib) {
+    const pdfDoc = await PDFLib.PDFDocument.load(snapshot)
+
+    const numberOfPages = pdfDoc.getPages().length;
+
+    let pagesArray = [];
+    let splitAfter = splitAfterPageArray.shift();
+    const subDocuments = [];
+
+    for (let i = 0; i < numberOfPages; i++) {
+        if(i > splitAfter && pagesArray.length > 0) {
+            subDocuments.push(await createSubDocument(pdfDoc, pagesArray, PDFLib));
+            splitAfter = splitAfterPageArray.shift();
+            pagesArray = [];
+        }
+        pagesArray.push(i);        
+    }
+    subDocuments.push(await createSubDocument(pdfDoc, pagesArray, PDFLib));
+    pagesArray = [];
+
+    return subDocuments;
+};

shared-operations/index.js

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+
+export {};

shared-operations/package.json

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+{
+  "name": "shared-operations",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "type": "module",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC"
+}