This package is developed only for test purposes. It is developed for merging pdf documents. All the functionalities build on pdfjs package.
npm i pdf-merger-trvl --save
const pdfMerger=require('pdf-merger-trvl');
var merger=new pdfMerger();
merger.add('pdf1.pdf'); //merge all pages. parameter is the path to file and filename.
merger.add('pdf2.pdf', [2]); // merge only page 2
merger.add('pdf3.pdf', '1to2'); //merge pages 1 to 2
merger.add('pdf2.pdf', [1,3]); // merge the pages 1 and 3
merger.save('merged.pdf'); //save under given name