Merging PDF Documents in JavaScript PDF Library

23 Jul 20268 minutes to read

The JavaScript PDF Library supports merging multiple PDF documents into a single file and importing pages from one document to another. This guide covers three common scenarios:

  • Importing a Page Range — copy the full range of pages from one document to another.
  • Importing from Multiple Documents — import selected page ranges from several source PDFs at specified positions.
  • Importing a Page with Optimization Options — import a single page with rotation, resource optimization, and grouped form fields.

Importing a Page Range

This section explains how to import a range of pages from a source PDF into a destination document using the importPageRange method.

import { PdfDocument } from '@syncfusion/ej2-pdf';

// Load an existing PDF document
let destination: PdfDocument = new PdfDocument(data1);
// Load another existing PDF document
let sourceDocument: PdfDocument = new PdfDocument(data2);
// Import the full range of pages from the source document into the destination
destination.importPageRange(sourceDocument, 0, sourceDocument.pageCount-1);
// Save the output PDF
destination.save('Output.pdf');
// Destroy the documents to free resources
destination.destroy();
sourceDocument.destroy();
// Load an existing PDF document
var destination= new ej.pdf.PdfDocument(data1);
// Load another existing PDF document
var sourceDocument = new ej.pdf.PdfDocument(data2);
// Import the full range of pages from the source document into the destination
destination.importPageRange(sourceDocument, 0, sourceDocument.pageCount-1);
// Save the output PDF
destination.save('Output.pdf');
// Destroy the documents to free resources
destination.destroy();
sourceDocument.destroy();

Importing from Multiple Documents

This section demonstrates how to import selected page ranges from multiple source PDFs into a destination document at specified positions using the importPageRange method and PdfPageImportOptions. This is useful for merging selected page ranges from different PDFs into one document.

import { PdfDocument, PdfPageImportOptions } from '@syncfusion/ej2-pdf';

// Load an existing PDF document
let destination: PdfDocument = new PdfDocument(data1);
// Load another existing PDF document
let sourceDocument1: PdfDocument = new PdfDocument(data2);
// Options to customize the import of PDF pages
let options: PdfPageImportOptions = new PdfPageImportOptions();
// Sets the target page index to insert the imported pages
options.targetIndex = 3;
// Import 5 pages from page index 2 to 6 into the destination document and insert them at index 3
destination.importPageRange(sourceDocument1, 2, 6, options);
// Load another existing PDF document
let sourceDocument2: PdfDocument = new PdfDocument(data3);
// Options to customize the import of PDF pages
options = new PdfPageImportOptions();
// Sets the target page index to insert the imported pages
options.targetIndex = 7;
// Import 4 pages from page index 0 to 3 into the destination document and insert them at index 7
destination.importPageRange(sourceDocument2, 0, 3, options);
// Save the output PDF
destination.save('Output.pdf');
// Destroy the documents to free resources
destination.destroy();
sourceDocument1.destroy();
sourceDocument2.destroy();
// Load an existing PDF document
var destination = new ej.pdf.PdfDocument(data1);
// Load another existing PDF document
var sourceDocument1 = new ej.pdf.PdfDocument(data2);
// Options to customize the import of PDF pages
var options = new ej.pdf.PdfPageImportOptions();
// Sets the target page index to insert the imported pages
options.targetIndex = 3;
// Import 5 pages from page index 2 to 6 into the destination document and insert them at index 3
destination.importPageRange(sourceDocument1, 2, 6, options);
// Load another existing PDF document
var sourceDocument2 = new ej.pdf.PdfDocument(data3);
// Options to customize the import of PDF pages
options = new ej.pdf.PdfPageImportOptions();
// Sets the target page index to insert the imported pages
options.targetIndex = 7;
// Import 4 pages from page index 0 to 3 into the destination document and insert them at index 7
destination.importPageRange(sourceDocument2, 0, 3, options);
// Save the output PDF
destination.save('Output.pdf');
// Destroy the documents to free resources
destination.destroy();
sourceDocument1.destroy();
sourceDocument2.destroy();

Importing a Page with Optimization Options

This example imports a single page from a source PDF into a destination document with rotation, resource optimization, and grouped form fields using the PdfPageImportOptions class. The targetIndex property is optional. If not specified, the page is appended at the end of the destination document.

PdfPageImportOptions Properties

Property Type Description
targetIndex number The destination page index at which the imported page is inserted. Optional; defaults to append.
rotation PdfRotationAngle The rotation angle applied to the imported page.
optimizeResources boolean When true, merges duplicated resources (fonts, images) to reduce file size.
groupFormFields boolean When true, groups form fields together for consistent appearance across viewers. 
import { PdfDocument, PdfPage, PdfPageImportOptions, PdfRotationAngle } from '@syncfusion/ej2-pdf';

// Load an existing PDF document
let destination: PdfDocument = new PdfDocument(data1);
// Load another existing PDF document
let sourceDocument: PdfDocument = new PdfDocument(data2);
// Access the first page of the source document
let pageToImport: PdfPage = sourceDocument.getPage(0);
// Options to customize the support of import PDF pages
let options: PdfPageImportOptions = new PdfPageImportOptions();
// Sets the rotation angle
options.rotation = PdfRotationAngle.angle270;
// Enables resource optimization when importing pages
options.optimizeResources = true;
// Groups form fields together while importing pages
options.groupFormFields = true;
// Import the page into the destination document (appended at the end since targetIndex is not set)
destination.importPage(pageToImport, sourceDocument, options);
// Save the output PDF
destination.save('Output.pdf');
// Destroy the documents to free resources
destination.destroy();
sourceDocument.destroy();
// Load an existing PDF document
var destination = new ej.pdf.PdfDocument(data1);
// Load another existing PDF document
var sourceDocument = new ej.pdf.PdfDocument(data2);
// Access the first page of the source document
var pageToImport = sourceDocument.getPage(0);
// Options to customize the support of import PDF pages
var options = new ej.pdf.PdfPageImportOptions();
// Sets the rotation angle
options.rotation = PdfRotationAngle.angle270;
// Enables resource optimization when importing pages
options.optimizeResources = true;
// Groups form fields together while importing pages
options.groupFormFields = true;
// Import the page into the destination document (appended at the end since targetIndex is not set)
destination.importPage(pageToImport, sourceDocument, options);
// Save the output PDF
destination.save('Output.pdf');
// Destroy the documents to free resources
destination.destroy();
sourceDocument.destroy();

Additional Resources