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

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

const muhammara = require("../muhammara");
const hummusUtils = require("./utils");

/**
 * Append pages from the other pdf to the current pdf
 * @name appendPage
 * @function
 * @memberof Recipe
 * @param {string} pdfSrc - The path for the other pdf.
 * @param {number|number[]} pages - The page number or the array of page numbers to be appended.
 */
exports.appendPage = function appendPage(pdfSrc, pages = []) {
  if (!Array.isArray(pages) && !isNaN(pages)) {
    pages = [pages];
  }
  // Using stream so it can be closed to release reader resource (Issue #61)
  const instream = new muhammara.PDFRStreamForFile(pdfSrc);
  const pdfReader = muhammara.createReader(instream);
  const pageCount = pdfReader.getPagesCount();
  instream.close();

  // prevent unmatched pagenumber
  const transformPageNumber = (pageNum) => {
    pageNum = pageNum > pageCount ? pageCount : pageNum;
    pageNum = pageNum < 1 ? 1 : pageNum;
    return pageNum - 1;
  };
  pages = pages.map((element) => {
    if (Array.isArray(element)) {
      return [transformPageNumber(element[0]), transformPageNumber(element[1])];
    } else {
      return [transformPageNumber(element), transformPageNumber(element)];
    }
  });
  if (pages.length > 0) {
    hummusUtils.appendPDFPagesFromPDFWithAnnotations(this.writer, pdfSrc, {
      specificRanges: pages,
    });
  } else {
    hummusUtils.appendPDFPagesFromPDFWithAnnotations(this.writer, pdfSrc);
  }
  return this;
};