PDFApp.js

/**
 * GitHub  https://github.com/tanaikech/PDFApp<br>
 * Library name
 * @type {string}
 * @const {string}
 * @readonly
 */
var appName = "PDFApp";

/**
 * ### Description
 * Give the source PDF blob. This method is used with other methods.
 * 
 * @param {Object} blob PDF blob.
 * @return {PDFApp}
 */
function setPDFBlob(blob = null) {
  if (!blob || blob.toString() != "Blob" || blob.getContentType() != MimeType.PDF) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  this.pdfBlob = blob;
  return this;
}

/**
 * ### Description
 * When you want to use the standard font, please use this method.
 * You can select one of them from the below page.
 * ref: https://pdf-lib.js.org/docs/api/enums/standardfonts
 * This method is used with other methods.
 * 
 * @param {String} name Font name of the built-in standard fonts.
 * @return {PDFApp}
 */
function useStandardFont(name = null) {
  this.useStandardFont = name;
  return this;
}

/**
 * ### Description
 * When you want to use the custom font, please use this method. This method is used with other methods.
 * 
 * @param {Object} blob Blob of custom font. TTF and OTF files can be used.
 * @return {PDFApp}
 */
function useCustomFont(blob = null) {
  this.useCustomFont = blob;
  return this;
}

/**
 * ### Description
 * Export specific pages from a PDF blob.
 * 
 * @param {number[]} pageNumbers Array including the page numbers you want to export.
 * @return {promise} PDF Blob including the exported pages.
 */
function exportPages(pageNumbers) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.exportPages(pdfBlob, pageNumbers);
}

/**
 * ### Description
 * Get PDF metadata from a PDF blob.
 * 
 * @return {promise} PDF metadata.
 */
function getMetadata() {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.getMetadata(pdfBlob);
}

/**
 * ### Description
 * Update PDF metadata of a PDF blob.
 * 
 * @param {Object} object Object for updading PDF metadata.
 * @return {promise} Updated PDF blob.
 */
function udpateMetadata(object) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.udpateMetadata(pdfBlob, object);
}

/**
 * ### Description
 * Reorder pages of a PDF blob.
 * 
 * @param {Object} object Object for reordering pages of PDF.
 * @return {promise} Updated PDF blob.
 */
function reorderPages(object) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.reorderPages(pdfBlob, object);
}

/**
 * ### Description
 * Merge multiple PDF files in a single PDF.
 * 
 * @param {Object[]} pdfBlobs Array including PDF Blobs for merging in a single PDF.
 * @return {promise} Merged PDF Blob.
 */
function mergePDFs(pdfBlobs) {
  if (!pdfBlobs.every(blob => blob && blob.toString() == "Blob" && blob.getContentType() == MimeType.PDF)) {
    throw new Error("Please set the source PDF blobs for merging in a single PDF.");
  }
  const PDFA = new PDFApp(this);
  return PDFA.mergePDFs(pdfBlobs);
}

/**
 * ### Description
 * Convert PDF pages to PNG images.
 * ref: https://tanaikech.github.io/2023/01/11/converting-all-pages-in-pdf-file-to-png-images-using-google-apps-script/
 *
 * @return {promise} PDF Blob.
 */
function convertPDFToPng() {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.convertPDFToPng(pdfBlob);
}

/**
 * ### Description
 * Get values from PDF Form.
 * ref: https://tanaikech.github.io/2023/08/02/retrieving-and-putting-values-for-pdf-forms-using-google-apps-script/
 *
 * @return {promise} Object including the values of PDF Form.
 */
function getValuesFromPDFForm() {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.getValuesFromPDFForm(pdfBlob);
}

/**
 * ### Description
 * Set values to PDF Form.
 * ref: https://tanaikech.github.io/2023/08/02/retrieving-and-putting-values-for-pdf-forms-using-google-apps-script/
 *
 * @param {Object} object Object for putting values to PDF Form.
 * @return {promise} Object including the values of PDF Form.
 */
function setValuesToPDFForm(object) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.setValuesToPDFForm(pdfBlob, object);
}

/**
 * ### Description
 * Create PDF Form By Google Slide template.
 * ref: https://medium.com/google-cloud/creating-pdf-forms-from-google-slide-template-using-google-apps-script-cef35e7d9822
 *
 * @param {String} id File ID of Google Slide template.
 * @param {Object} object Object for setting.
 * @return {promise} Object including the values of PDF Form.
 */
function createPDFFormBySlideTemplate(id, object) {
  const PDFA = new PDFApp(this);
  return PDFA.createPDFFormBySlideTemplate(id, object);
}

/**
 * ### Description
 * Embed objects into PDF blob.
 * ref: https://medium.com/google-cloud/embedding-objects-in-pdf-using-google-apps-script-ddbee857c642
 *
 * @param {Object} pdfBlob Blob of PDF data for embedding objects.
 * @param {Object} object Object including the values for embedding objects.
 * @return {promise} PDF Blob.
 */
function embedObjects(object) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.embedObjects(pdfBlob, object);
}

/**
 * ### Description
 * Insert header and/or footer into PDF blob.
 *
 * @param {Object} pdfBlob Blob of PDF data for embedding objects.
 * @param {Object} object Object including the values for inserting header and footer.
 * @return {promise} PDF Blob.
 */
function insertHeaderFooter(object) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.insertHeaderFooter(pdfBlob, object);
}

/**
 * ### Description
 * Split each page of a PDF to an individual PDF file.
 *
 * @return {promise} PDF Blobs.
 */
function splitPDF() {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.splitPDF(pdfBlob);
}

/**
 * ### Description
 * Add page numbers to PDF.
 * 
 * @param {Object} object Object including the format of page number.
 * @return {promise} PDF Blobs.
 */
function addPageNumbers(object) {
  if (!this.pdfBlob) {
    throw new Error("Please set the source PDF blob using the setPDFBlob method.");
  }
  const pdfBlob = this.pdfBlob;
  const PDFA = new PDFApp(this);
  return PDFA.addPageNumbers(pdfBlob, object);
}


/**
 * ### Description
 * This is a Class PDFApp for managing PDF using Google Apps Script.
 *
 * Author: Tanaike ( https://tanaikech.github.io/ )
 */
class PDFApp {
  /**
   * ### Description
   * Constructor of this class.
   *
   * @return {void}
   */
  constructor(e) {
    this.cdnjs = "https://cdn.jsdelivr.net/npm/pdf-lib/dist/pdf-lib.min.js"; // or "https://cdnjs.cloudflare.com/ajax/libs/pdf-lib/1.17.1/pdf-lib.min.js"
    this.cdnFontkit = "https://unpkg.com/@pdf-lib/fontkit/dist/fontkit.umd.min.js";
    this.loadPdfLib_();
    if (e.useCustomFont && e.useCustomFont.toString() == "Blob") {
      this.loadFontkit_();
      this.customFont = e.useCustomFont;
    } else if (e.useStandardFont && typeof e.useStandardFont == "string") {
      this.standardFont = e.useStandardFont;
    }
  }

  /**
   * ### Description
   * Export specific pages from a PDF blob.
   * ref: https://medium.com/google-cloud/exporting-specific-pages-from-a-pdf-as-a-new-pdf-using-google-apps-script-2f22d07b4618
   *
   * @param {Object} pdfBlob Blob of PDF data by retrieving with Google Apps Script.
   * @param {number[]} pageNumbers Array including the page numbers you want to export.
   * @return {promise} PDF Blob including the exported pages.
   */
  exportPages(pdfBlob, pageNumbers) {
    if (!pageNumbers || !Array.isArray(pageNumbers) || pageNumbers.length == 0) {
      throw new Error("Please set the page numbers you want to export.");
    }
    return new Promise(async (resolve, reject) => {
      try {
        const pdfData = await this.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const pdfDoc = await this.PDFLib.PDFDocument.create();
        const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
        pages.forEach((page, i) => {
          if (pageNumbers.includes(i + 1)) {
            pdfDoc.addPage(page);
          }
        });
        const bytes = await pdfDoc.save();
        resolve(Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`));
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Get PDF metadata from a PDF blob.
   * ref: https://medium.com/google-cloud/management-of-pdf-metadata-using-google-apps-script-60fd41f4fc16
   *
   * @param {Object} pdfBlob Blob of PDF data by retrieving with Google Apps Script.
   * @return {promise} PDF metadata.
   */
  getMetadata(pdfBlob) {
    return new Promise(async (resolve, reject) => {
      const keys = ["title", "subject", "author", "creator", "creationDate", "modificationDate", "keywords", "producer"];
      const pdfData = await this.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
      try {
        const metadata = keys.reduce((o, k) => ((o[k] = pdfData[`get${k.charAt(0).toUpperCase() + k.slice(1)}`]() || null), o), {});
        metadata.numberOfPages = pdfData.getPageCount();
        const pdfDoc = await this.PDFLib.PDFDocument.create();
        const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
        metadata.pageInfo = pages.map((page, i) => {
          const { width, height } = page.getSize();
          const { x, y } = page.getPosition();
          return { page: i + 1, pageWidth: width, pageHeight: height, defaultPositionX: x, defaultPositionY: y };
        });
        resolve(metadata);
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Update PDF metadata of a PDF blob.
   * ref: https://medium.com/google-cloud/management-of-pdf-metadata-using-google-apps-script-60fd41f4fc16
   *
   * @param {Object} pdfBlob Blob of PDF data by retrieving with Google Apps Script.
   * @param {Object} object Object including the values for updating metadata.
   * @return {promise} PDF Blob.
   */
  udpateMetadata(pdfBlob, object) {
    if (typeof object != "object" || Object.keys(object).length == 0) {
      throw new Error("Please set valid object for updating PDF metadata.");
    }
    const self = this;
    return new Promise(async (resolve, reject) => {
      const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
      const keys = ["title", "subject", "author", "creator", "creationDate", "modificationDate", "keywords", "producer"];
      try {
        Promise.all(
          keys.map((k) =>
            new Promise(async (r, rj) => {
              try {
                if (object.hasOwnProperty(k)) {
                  const f = `set${k.charAt(0).toUpperCase() + k.slice(1)}`;
                  if (k == "title") {
                    await pdfData[f](...object[k]);
                  } else {
                    if (["creationDate", "modificationDate"].includes(k)) {
                      object[k] = new Date(object[k]);
                    } else if (k == "keywords") {
                      object[k] = JSON.parse(JSON.stringify(object[k]));
                    }
                    await pdfData[f](object[k]);
                  }
                  r("Done");
                }
              } catch (err) {
                rj(err);
              }
            })
          )
        )
          .then(async (_) => {
            const bytes = await pdfData.save();
            const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`);
            resolve(newBlob);
          })
          .catch((err) => console.log(err));
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Update PDF metadata of a PDF blob.
   * ref: https://medium.com/google-cloud/changing-order-of-pages-in-pdf-file-using-google-apps-script-f6b3de05d7df
   *
   * @param {Object} pdfBlob Blob of PDF data by retrieving with Google Apps Script.
   * @param {Object} object Object including the values for reordering pages.
   * @return {promise} PDF Blob.
   */
  reorderPages(pdfBlob, object) {
    if (typeof object != "object" || Object.keys(object).length == 0) {
      throw new Error("Please set valid object for reordering PDF pages.");
    }
    const self = this;
    return new Promise(async (resolve, reject) => {
      const { newOrderOfpages, ignoreSkippedPages } = object;
      const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
      const numberOfPages = pdfData.getPageCount();
      const maxPage = Math.max(...newOrderOfpages);
      if (numberOfPages < maxPage || numberOfPages < newOrderOfpages.length) {
        reject("Maximum page in the order of pages is over than the maximum page of the original PDF file.");
      }
      let skippedPages = [];
      if (!ignoreSkippedPages && numberOfPages > newOrderOfpages.length) {
        skippedPages = [...Array(numberOfPages)].map((_, i) => i + 1).filter(e => !newOrderOfpages.includes(e));
      }
      const pdfDoc = await self.PDFLib.PDFDocument.create();
      const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
      [...newOrderOfpages, ...skippedPages].forEach(e => pdfDoc.addPage(pages[e - 1]));
      const bytes = await pdfDoc.save();
      const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`);
      resolve(newBlob);
    });
  }

  /**
   * ### Description
   * Merge multiple PDF files in a single PDF.
   * ref: https://tanaikech.github.io/2023/01/10/merging-multiple-pdf-files-as-a-single-pdf-file-using-google-apps-script/
   *
   * @param {Object[]} pdfBlobs Array including PDF Blobs for merging in a single PDF.
   * @return {promise} PDF Blob.
   */
  mergePDFs(pdfBlobs) {
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const data = pdfBlobs.map(blob => new Uint8Array(blob.getBytes()));
        const pdfDoc = await self.PDFLib.PDFDocument.create();
        for (let i = 0; i < data.length; i++) {
          const pdfData = await self.PDFLib.PDFDocument.load(data[i]);
          const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
          pages.forEach(page => pdfDoc.addPage(page));
        }
        const bytes = await pdfDoc.save();
        const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, "new_PDFFile.pdf");
        resolve(newBlob);
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Convert PDF pages to PNG images.
   * ref: https://tanaikech.github.io/2023/01/11/converting-all-pages-in-pdf-file-to-png-images-using-google-apps-script/
   *
   * @param {Object} pdfBlob Blob of PDF data.
   * @return {promise} PDF Blob.
   */
  convertPDFToPng(pdfBlob) {
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const pageLength = pdfData.getPageCount();
        console.log(`Total pages: ${pageLength}`);
        const obj = { imageBlobs: [], fileIds: [] };
        const token = ScriptApp.getOAuthToken();
        for (let i = 0; i < pageLength; i++) {
          console.log(`Processing page: ${i + 1}`);
          const pdfDoc = await self.PDFLib.PDFDocument.create();
          const [page] = await pdfDoc.copyPages(pdfData, [i]);
          pdfDoc.addPage(page);
          const bytes = await pdfDoc.save();
          const blob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `temp_page${i + 1}.pdf`);
          const id = DriveApp.createFile(blob).getId();
          Utilities.sleep(3000); // This is used for preparing the thumbnail of the created file.
          const res = UrlFetchApp.fetch(
            `https://drive.google.com/thumbnail?id=${id}&sz=w1000`,
            {
              headers: { authorization: "Bearer " + token },
              muteHttpExceptions: true
            }
          );
          if (res.getResponseCode() != 200) {
            reject(res.getContentText());
            return;
          }
          const imageBlob = res.getBlob().setName(`page${i + 1}.png`);
          obj.imageBlobs.push(imageBlob);
          obj.fileIds.push(id);
        }
        obj.fileIds.forEach(id => DriveApp.getFileById(id).setTrashed(true));
        resolve(obj.imageBlobs);
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Get values from PDF Form.
   * ref: https://medium.com/google-cloud/retrieving-and-putting-values-for-pdf-forms-using-google-apps-script-92412a7cf0af
   *
   * @param {Object} pdfBlob Blob of PDF data.
   * @return {promise} Object including the values of PDF Form.
   */
  getValuesFromPDFForm(pdfBlob) {
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const form = pdfData.getForm();
        const { PDFTextField, PDFDropdown, PDFCheckBox, PDFRadioGroup } = self.PDFLib;
        const obj = form.getFields().map(function (f) {
          const retObj = { name: f.getName() };
          if (f instanceof PDFTextField) {
            retObj.value = f.getText();
            retObj.type = "Textbox";
          } else if (f instanceof PDFDropdown) {
            retObj.value = f.getSelected();
            retObj.options = f.getOptions();
            retObj.type = "Dropdown";
          } else if (f instanceof PDFCheckBox) {
            retObj.value = f.isChecked();
            retObj.type = "Checkbox";
          } else if (f instanceof PDFRadioGroup) {
            retObj.value = f.getSelected();
            retObj.options = f.getOptions();
            retObj.type = "Radiobutton";
          } else {
            retObj.type = "Unsupported type";
          }
          return retObj;
        });
        resolve(obj);
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Set values to PDF Form.
   * ref: https://medium.com/google-cloud/retrieving-and-putting-values-for-pdf-forms-using-google-apps-script-92412a7cf0af
   *
   * @param {Object} pdfBlob Blob of PDF data.
   * @param {Object} object Object for putting values to PDF Form.
   * @return {promise} Object including the values of PDF Form.
   */
  setValuesToPDFForm(pdfBlob, object) {
    if (!object.values || !Array.isArray(object.values)) {
      throw new Error("Please set valid values.");
    }
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const form = pdfData.getForm();
        if (self.standardFont || self.customFont) {
          await self.setCustomFont_(pdfData, form, { standardFont: self.standardFont, customFont: self.customFont });
        }
        const { PDFTextField, PDFDropdown, PDFCheckBox, PDFRadioGroup } = self.PDFLib;
        for (let { name, value } of object.values) {
          const field = form.getField(name);
          if (field instanceof PDFTextField) {
            field.setText(value);
          } else if (field instanceof PDFDropdown) {
            if (field.isMultiselect()) {
              for (let v of value) {
                field.select(v);
              }
            } else {
              field.select(value);
            }
          } else if (field instanceof PDFCheckBox) {
            field[value ? "check" : "uncheck"]();
          } else if (field instanceof PDFRadioGroup) {
            field.select(value);
          }
        }
        const bytes = await pdfData.save();
        const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`);
        resolve(newBlob);
      } catch (e) {
        reject(e);
      }
    });
  }

  /**
   * ### Description
   * Create PDF Form By Google Slide template.
   * ref: https://medium.com/google-cloud/creating-pdf-forms-from-google-slide-template-using-google-apps-script-cef35e7d9822
   *
   * @param {String} id File ID of Google Slide template.
   * @param {Object} object Object for setting.
   * @return {promise} Object including the values of PDF Form.
   */
  createPDFFormBySlideTemplate(id, object) {
    if (!id || id == "") {
      throw new Error("Please set the file ID of Google Slide including the template for PDF Form.");
    }
    if (!object || !object.values || !Array.isArray(object.values) || object.values.length == 0) {
      throw new Error("Please set valid object for creating PDF Form from Google Slide template.");
    }
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const obj = self.getObjectFromSlide_(id, object.values);
        const newBlob = await self.createFields_(self, obj);
        resolve(newBlob);
      } catch (e) {
        reject(e);
      }
    });
  }

  /**
   * ### Description
   * Embed objects into PDF blob.
   * ref: https://medium.com/google-cloud/embedding-objects-in-pdf-using-google-apps-script-ddbee857c642
   *
   * @param {Object} pdfBlob Blob of PDF data for embedding objects.
   * @param {Object} object Object including the values for embedding objects.
   * @return {promise} PDF Blob.
   */
  embedObjects(pdfBlob, object) {
    if (!object || typeof object != "object") {
      throw new Error("Please an object for embeddig the objects.");
    }
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const { updatedObject, customFontCheck } = self.updateObject_(object);
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const numberOfPages = pdfData.getPageCount();
        const pdfDoc = await self.PDFLib.PDFDocument.create();
        if (customFontCheck) {
          self.loadFontkit_();
          pdfDoc.registerFontkit(this.fontkit);
        }
        const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
        for (let i = 0; i < pages.length; i++) {
          const page = pages[i];
          const forPage = updatedObject[`page${i + 1}`];
          if (forPage) {
            for (let j = 0; j < forPage.length; j++) {
              const o = forPage[j];
              if (o.imageFileId) {
                const image = await pdfDoc[o.method](o.imageBytes);
                if (o.scale) {
                  const updatedImage = image.scale(o.scale);
                  o.width = o.width || updatedImage.width;
                  o.height = o.height || updatedImage.height;
                } else {
                  o.width = o.width || image.width;
                  o.height = o.height || image.height;
                }
                delete o.imageBytes;
                delete o.method;
                delete o.imageFileId;
                delete o.scale;
                page.drawImage(image, o);
              } else if (o.text) {
                if (o.standardFont || o.customFont) {
                  o.font = await pdfDoc.embedFont(o.standardFont ? this.PDFLib.StandardFonts[o.standardFont] : o.customFont);
                }
                page.drawText(o.text, o);
              }
            }
          }
          pdfDoc.addPage(page);
        }
        const bytes = await pdfDoc.save();
        const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`);
        resolve(newBlob);
      } catch (e) {
        reject(e);
      }
    });
  }

  /**
   * ### Description
   * Insert header and/or footer into PDF blob.
   *
   * @param {Object} pdfBlob Blob of PDF data for embedding objects.
   * @param {Object} object Object including the values for inserting header and footer.
   * @return {promise} PDF Blob.
   */
  insertHeaderFooter(pdfBlob, object) {
    if (!object || typeof object != "object") {
      throw new Error("Please an object for embeddig the objects.");
    }
    let self = this;
    return new Promise(async function (resolve, reject) {
      try {
        const pdfDoc = await self.PDFLib.PDFDocument.create();
        const form = pdfDoc.getForm();
        let font = null;
        if (self.standardFont || self.customFont) {
          await self.setCustomFont_(pdfDoc, form, { standardFont: self.standardFont, customFont: self.customFont });
          font = await pdfDoc.embedFont(self.standardFont ? self.PDFLib.StandardFonts[self.standardFont] : new Uint8Array(self.customFont.getBytes()));
        }
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const numberOfPages = pdfData.getPageCount();
        const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
        const { header, footer } = object;
        const headers = header ? Object.entries(header).map(([k, v]) => [`header.${k}`, v]) : [];
        const footers = footer ? Object.entries(footer).map(([k, v]) => [`footer.${k}`, v]) : [];
        const sortOrder = ["LEFT", "CENTER", "RIGHT"];
        [footers, headers].forEach((f, _, x) => f.sort((a, b) => {
          const i1 = sortOrder.findIndex(e => a[0].includes(e.toLowerCase()));
          const i2 = sortOrder.findIndex(e => b[0].includes(e.toLowerCase()));
          const vlen = x.length;
          return (i1 > -1 ? i1 : vlen) - (i2 > -1 ? i2 : vlen);
        }));
        const alignObj = { "center": "Center", "left": "Left", "right": "Right" };
        for (let i = 0; i < numberOfPages; i++) {
          const pageNumber = i + 1;
          const page = pdfDoc.addPage(pages[i]);
          const pageHeight = page.getHeight();
          const pageWidth = page.getWidth();
          if (headers.length > 0) {
            const sizeWidthHead = pageWidth / (headers.length);
            for (let j = 0; j < headers.length; j++) {
              const [k, v] = headers[j];
              const o = {
                borderWidth: v.borderWidth || 0,
                x: j * sizeWidthHead,
                y: pageHeight - ((v.yOffset || 0) + (v.height || 20)),
                width: sizeWidthHead,
                height: v.height || 30,
                ...v,
                font,
              };
              await self.addHeaderFooterFields_(self, { page, form, pageNumber, k, v, o, alignObj, font });
            }
          }
          if (footers.length > 0) {
            const sizeWidthFoot = pageWidth / (footers.length);
            for (let j = 0; j < footers.length; j++) {
              const [k, v] = footers[j];
              const o = {
                borderWidth: v.borderWidth || 0,
                x: j * sizeWidthFoot,
                y: v.yOffset || 0,
                width: sizeWidthFoot,
                height: v.height || 30,
                ...v,
                font,
              };
              await self.addHeaderFooterFields_(self, { page, form, pageNumber, k, v, o, alignObj, font });
            }
          }
        }
        const bytes = await pdfDoc.save();
        const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`);
        resolve(newBlob);
      } catch (e) {
        reject(e);
      }
    });
  }

  /**
   * ### Description
   * Split each page of a PDF to an individual PDF file.
   *
   * @param {Object} pdfBlob Blob of PDF data.
   * @return {promise} PDF Blob.
   */
  splitPDF(pdfBlob) {
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const pageLength = pdfData.getPageCount();
        console.log(`Total pages: ${pageLength}`);
        const pdfBlobs = [];
        for (let i = 0; i < pageLength; i++) {
          console.log(`Processing page: ${i + 1}`);
          const pdfDoc = await self.PDFLib.PDFDocument.create();
          const [page] = await pdfDoc.copyPages(pdfData, [i]);
          pdfDoc.addPage(page);
          const bytes = await pdfDoc.save();
          const blob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `page${i + 1}.pdf`);
          pdfBlobs.push(blob);
        }
        resolve(pdfBlobs);
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Add page numbers to PDF.
   * 
   * @param {Object} pdfBlob Blob of PDF data.
   * @param {Object} object Object including the format of page number.
   * @return {promise} PDF Blobs.
   */
  addPageNumbers(pdfBlob, object) {
    if (!object || typeof object != "object" || !["size", "x", "y"].every(e => e in object)) {
      throw new Error("Please an object for adding page numbers.");
    }
    const self = this;
    return new Promise(async (resolve, reject) => {
      try {
        const pdfData = await self.getPDFObjectFromBlob_(pdfBlob).catch(err => reject(err));
        const pdfDoc = await self.PDFLib.PDFDocument.create();
        (await pdfDoc.copyPages(pdfData, pdfData.getPageIndices()))
          .forEach((page, i) => {
            if (isNaN(object.x)) {
              const { width } = page.getSize();
              const obj = { center: width / 2, left: 20, right: width - 20 };
              const pageFormatObj = { ...object };
              pageFormatObj.x = obj[object.x];
              page.drawText(`${i + 1}`, pageFormatObj);
            } else {
              page.drawText(`${i + 1}`, object);
            }
            pdfDoc.addPage(page);
          });
        const bytes = await pdfDoc.save();
        const newBlob = Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${pdfBlob.getName()}`);
        resolve(newBlob);
      } catch (err) {
        reject(err);
      }
    });
  }

  /**
   * ### Description
   * Create fields of PDF Form.
   *
   * @param {Object} self this of this Class object.
   * @param {Object} object Object for creating fields.
   * @return {Object} Blob of new PDF.
   */
  addHeaderFooterFields_(self, object) {
    const { page, form, pageNumber, k, v, o, alignObj, font } = object;
    const fieldName = `${k}.${pageNumber}`;
    const textBox = form.createTextField(fieldName);
    if (v.text) {
      textBox.setText(v.text);
    }
    if (v.alignment) {
      textBox.setAlignment(self.PDFLib.TextAlignment[alignObj[v.alignment.toLowerCase()]]);
    }
    textBox.disableScrolling();
    textBox.disableMultiline();
    textBox.enableReadOnly();
    ["x", "y", "width", "text"].forEach(e => delete v[e]);
    textBox.addToPage(page, o);
  }

  /**
   * ### Description
   * Create fields of PDF Form.
   *
   * @param {Object} self this of this Class object.
   * @param {Object} object Object for creating fields.
   * @return {Object} Blob of new PDF.
   */
  async createFields_(self, object) {
    const { obj, blob } = object;
    const pdfDoc = await self.PDFLib.PDFDocument.create();
    const form = pdfDoc.getForm();
    if (self.standardFont || self.customFont) {
      await self.setCustomFont_(pdfDoc, form, { standardFont: self.standardFont, customFont: self.customFont });
    }
    const pdfData = await self.getPDFObjectFromBlob_(blob).catch(err => reject(err));
    const numberOfPages = pdfData.getPageCount();
    const pages = await pdfDoc.copyPages(pdfData, pdfData.getPageIndices());
    const xAxisOffset = 0.5;
    const yAxisOffset = 0.5;
    for (let i = 0; i < numberOfPages; i++) {
      const pageNumber = i + 1;
      const page = pdfDoc.addPage(pages[i]);
      const pageHeight = page.getHeight();
      const yOffset = pageHeight;
      obj[i].forEach((v, k) => {
        if (k == "checkbox") {
          v.forEach(t => {
            t.forEach(u => {
              const checkbox = form.createCheckBox(u.title);
              checkbox.addToPage(page, { x: u.leftOffset - xAxisOffset, y: yOffset - u.topOffset - u.height + yAxisOffset, width: u.width, height: u.height });
              self.setStyles_(checkbox, u);
            });
          });
        } else if (k == "radiobutton") {
          v.forEach((t, kk) => {
            const radio = form.createRadioGroup(`radiobutton.${kk}.page${pageNumber}`);
            t.forEach(u => {
              radio.addOptionToPage(u.title, page, { x: u.leftOffset - xAxisOffset, y: yOffset - u.topOffset - u.height + yAxisOffset, width: u.width, height: u.height });
              self.setStyles_(radio, u);
            });
          });
        } else if (k == "textbox") {
          v.forEach(t => {
            t.forEach(u => {
              const textBox = form.createTextField(u.title);
              textBox.addToPage(page, {
                x: u.leftOffset - xAxisOffset,
                y: yOffset - u.topOffset - u.height + yAxisOffset,
                width: u.width,
                height: u.height,
              });
              self.setStyles_(textBox, u);
            });
          });
        } else if (k == "dropdownlist") {
          v.forEach(t => {
            t.forEach(u => {
              const drowdown = form.createDropdown(u.title);
              drowdown.addToPage(page, {
                x: u.leftOffset - xAxisOffset,
                y: yOffset - u.topOffset - u.height + yAxisOffset,
                width: u.width,
                height: u.height
              });
              self.setStyles_(drowdown, u);
            });
          });
        }
      });
    }
    const bytes = await pdfDoc.save();
    return Utilities.newBlob([...new Int8Array(bytes)], MimeType.PDF, `new_${blob.getName()}`);
  }

  /**
   * ### Description
   * Set custom font to PDF form.
   *
   * @param {Object} pdfDoc Object of PDF document.
   * @param {Object} form Object of PDF form.
   * @return {void}
   */
  async setCustomFont_(pdfDoc, form, { standardFont, customFont }) {
    let customfont;
    if (standardFont) {
      customfont = await pdfDoc.embedFont(this.PDFLib.StandardFonts[standardFont]);
    } else if (customFont) {
      pdfDoc.registerFontkit(this.fontkit);
      customfont = await pdfDoc.embedFont(new Uint8Array(customFont.getBytes()));
    }

    // Ref: https://github.com/Hopding/pdf-lib/issues/1152
    const rawUpdateFieldAppearances = form.updateFieldAppearances.bind(form);
    form.updateFieldAppearances = function () {
      return rawUpdateFieldAppearances(customfont);
    };

  }

  /**
   * ### Description
   * Set styles to the field of PDF form.
   *
   * @param {Object} instance Instance of field.
   * @param {Object} u Methods and values for setting the styles.
   * @return {Object} Object for creating the fields of PDF Form.
   */
  setStyles_(instance, u) {
    if (u.description.methods && u.description.methods.length > 0) {
      u.description.methods.forEach(({ method, value }) => {
        if (value && Array.isArray(value)) {
          value = [...value];
        }
        instance[method](value || null)
      });
    }
  }

  /**
   * ### Description
   * Get an object for creating the fields of PDF Form from Google Slide.
   *
   * @param {String} id File ID of Google Slide template.
   * @return {Object} Object for creating the fields of PDF Form.
   */
  getObjectFromSlide_(id, object) {
    const inputObj = object.reduce((o, e) => (o[e.shapeTitle] = e, o), {});
    const slide = SlidesApp.openById(id);
    const slides = slide.getSlides();
    const ar = slides.map((s, i) =>
      s.getShapes().reduce((ar, e) => {
        const t = e.getTitle().trim();
        if (t && inputObj[t]) {
          const page = i + 1;
          const [type, group, name] = t.split(".").map(f => f.trim());
          let setMethods = inputObj[t];
          if (type == "radiobutton" && inputObj[t] && inputObj[t].methods && inputObj[t].methods.length > 0) {
            const temp = JSON.parse(JSON.stringify(inputObj[t]));
            temp.methods.forEach(f => {
              if (f.method == "select") {
                f.value = `${f.value}.page${page}`;
              }
            });
            setMethods = temp;
          }
          ar.push({
            title: `${t}.page${page}`,
            page,
            type,
            group,
            name,
            shape: e,
            topOffset: e.getTop(),
            leftOffset: e.getLeft(),
            width: e.getWidth(),
            height: e.getHeight(),
            description: setMethods,
          });
        }
        return ar;
      }, [])
    );

    const duplicateCheckObj = ar.reduce((m, e) => {
      e.forEach(({ title }) => m.set(title, m.has(title) ? m.get(title) + 1 : 1));
      return m;
    }, new Map());
    const duplicateCheck = [...duplicateCheckObj].filter(([_, v]) => v > 1);
    if (duplicateCheck.length > 0) {
      temp.setTrashed(true);
      throw new Error(`Duplicate titles were found. The duplicated titles are "${duplicateCheck.map(([k]) => k).join(",")}".`);
    }

    ar.forEach(page => page.forEach(({ shape }) => shape.remove()));
    slide.saveAndClose();

    const obj = ar.map(d => d.reduce((m, e) => m.set(e.type, m.has(e.type) ? [...m.get(e.type), e] : [e]), new Map()));
    obj.forEach(page =>
      page.forEach((v, k, m) => m.set(k, v.reduce((mm, e) => mm.set(e.group, mm.has(e.group) ? [...mm.get(e.group), e] : [e]), new Map())))
    );
    const blob = DriveApp.getFileById(id).getBlob();
    return { obj, blob };
  }

  /**
   * ### Description
   * Update object.
   *
   * @param {Object} object Object for embedding objects into PDF.
   * @return {void}
   */
  updateObject_(object) {
    let customFontCheck = false;
    const updatedObject = Object.fromEntries(Object.entries(object).map(([k, p]) => [k, p.map(e => {
      if (e.imageFileId) {
        const imageBlob = DriveApp.getFileById(e.imageFileId).getBlob();
        const imageBytes = new Uint8Array(imageBlob.getBytes());
        const mimeType = imageBlob.getContentType();
        let method;
        if (mimeType == MimeType.PNG) {
          method = "embedPng";
        } else if (mimeType == MimeType.JPEG) {
          method = "embedJpg";
        } else {
          throw new Error("This image file cannot be used.");
        }
        e.method = method;
        e.imageBytes = imageBytes;
      } else if (e.text) {
        if (e.customFont) {
          customFontCheck = true;
          e.customFont = new Uint8Array(e.customFont.getBytes());
        }
      }
      return e;
    })]));
    return { updatedObject, customFontCheck };
  }

  /**
   * ### Description
   * Load pdf-lib. https://pdf-lib.js.org/docs/api/classes/pdfdocument
   *
   * @return {void}
   */
  loadPdfLib_() {
    this.loadJavascriptLibrary_(UrlFetchApp.fetch(this.cdnjs).getContentText().replace(/setTimeout\(.*?,.*?(\d*?)\)/g, "Utilities.sleep($1);return t();"));
  }

  /**
   * ### Description
   * Load fontkit. https://github.com/Hopding/fontkit
   *
   * @return {void}
   */
  loadFontkit_() {
    this.loadJavascriptLibrary_(UrlFetchApp.fetch(this.cdnFontkit).getContentText());
  }

  /**
   * ### Description
   * Load Javascript library in Google Apps Script project.
   *
   * @param {String} jsLib Javascript library as a string.
   * @return {void}
   */
  loadJavascriptLibrary_(jsLib) {
    eval(jsLib);
  }

  /**
   * ### Description
   * Get PDF object from PDF blob.
   *
   * @param {Object} blob PDF Blob retrieved by Google Apps Script.
   * @return {void}
   */
  async getPDFObjectFromBlob_(blob) {
    return await this.PDFLib.PDFDocument.load(new Uint8Array(blob.getBytes()));
  }
}