How to add multiple images to single tiff in nodejs?

Question

var ConvertTiff = require('tiff-to-png'),
converter = new ConvertTiff();
var filePath = __dirname + '\\tifffile\\mytifffile.tiff';
var filePAth1=__dirname + '\\images\\abc1.tiff';
var filePAth2=__dirname + '\\images\\abc1.tiff';

var tiffs =[filePAth1,filePAth2];
converter.progress = function(converted, total){
    console.log("File "+total);
};
converter.convertArray(tiffs, filePath);

Above code not creating single tiff with multiple pages. Please help me any suggestion.