The correct way to save a file using request module

SaveBinaryAsciiFile.js

SaveThePDF(url, filename) {
	const writeFile = denodeify(fs.writeFile);
	const requestPromised = denodeify(request.defaults({
		'gzip': true,
		headers: {
			'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.101 Safari/537.36',
			'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*\/*;q=0.8',
		}
	}), function(err, httpResponse, body) {
		// Convert 3 paramters to 2
		return [err, {httpResponse: httpResponse, body: body}];
	});
	
	return requestPromised({
		url: url,
		method: 'post',
		encoding: 'binary'
	}).then ( (response) => {
		return writeFile(filename, response.body, 'ascii');
	});
}