@aeolun/muhammara/lib/recipe/insertPage.js

Create, read and modify PDF files and streams. A drop in replacement for hummusjs PDF library

const muhammara = require("../muhammara");
const fs = require("fs");
const hummusUtils = require("./utils");
/**
 * Insert a page from the other pdf
 * @name insertPage
 * @function
 * @memberof Recipe
 * @param {number} afterPageNumber - The page number for insertion.
 * @param {string} pdfSrc - The path for the other pdf
 * @param {number} srcPageNumber - The page number to be insterted from the other pdf.
 */
exports.insertPage = function insertPage(
  afterPageNumber,
  pdfSrc,
  srcPageNumber
) {
  if (isNaN(afterPageNumber)) {
    throw new Error("The afterPageNumber is inValid.");
  }
  this.needToInsertPages = true;
  if (pdfSrc && srcPageNumber) {
    this.insertInformation = this.insertInformation || {};
    this.insertInformation[afterPageNumber] =
      this.insertInformation[afterPageNumber] || [];
    this.insertInformation[afterPageNumber].push({
      afterPageNumber,
      pdfSrc,
      srcPageNumber,
    });
  }
  return this;
};

exports._insertPages = function _insertPages() {
  if (!this.insertInformation) {
    throw new Error("No insertInformation");
  }
  const pagesForInsert = [
    0,
    ...Object.keys(this.metadata)
      .filter((item) => !isNaN(item))
      .map((item) => parseInt(item)),
  ];
  const unlinkList = [];
  const tmp = this.output + ".tmp.pdf";
  unlinkList.push(tmp);
  fs.renameSync(this.output, tmp);

  const pdfWriter = muhammara.createWriter(this.output);
  let lastInsertedOriginal = 0;
  pagesForInsert.forEach((pageNumber) => {
    const toAppendPage = pageNumber - 1;
    if (toAppendPage >= 0) {
      const specificRanges = [[lastInsertedOriginal, toAppendPage]];
      hummusUtils.appendPDFPagesFromPDFWithAnnotations(pdfWriter, tmp, {
        specificRanges,
      });
    }
    lastInsertedOriginal = pageNumber;

    const toInserts = this.insertInformation[pageNumber];
    if (toInserts) {
      toInserts.forEach((info) => {
        const specificRanges = [
          [info.srcPageNumber - 1, info.srcPageNumber - 1],
        ];
        hummusUtils.appendPDFPagesFromPDFWithAnnotations(
          pdfWriter,
          info.pdfSrc,
          { specificRanges }
        );
      });
    }
  });
  pdfWriter.end();

  unlinkList.forEach((item) => {
    setTimeout(() => {
      if (fs.existsSync(item)) {
        fs.unlinkSync(item);
      }
    });
  });
  return this;
};