51Degrees Device Detection Node.js  4.4

51Degrees Device Detection for Node.js


This example shows how to use 51Degrees on-premise device detection to determine details about a device based on its User-Agent and User-Agent Client Hint HTTP header values.

You will learn:

  1. How to create a Pipeline that uses 51Degrees on-premise device detection
  2. How to pass input data (evidence) to the Pipeline
  3. How to retrieve the results

This example is available in full on GitHub.

This example requires a local data file. The free 'Lite' data file can be acquired by pulling the git submodules under this repository (run `git submodule update --recursive`) or from the device-detection-data GitHub repository.

The Lite data file is only used for illustration, and has limited accuracy and capabilities. Find out about the more capable data files that are available on our pricing page

Required npm Dependencies:

  • fiftyone.pipeline.core
  • fiftyone.pipeline.engines
  • fiftyone.pipeline.engines.fiftyone
  • fiftyone.devicedetection.onpremise
/* *********************************************************************
* This Original Work is copyright of 51 Degrees Mobile Experts Limited.
* Copyright 2022 51 Degrees Mobile Experts Limited, Davidson House,
* Forbury Square, Reading, Berkshire, United Kingdom RG1 3EU.
* This Original Work is licensed under the European Union Public Licence
* (EUPL) v.1.2 and is subject to its terms as set out below.
* If a copy of the EUPL was not distributed with this file, You can obtain
* one at https://opensource.org/licenses/EUPL-1.2.
* The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
* amended by the European Commission) shall be deemed incompatible for
* the purposes of the Work and the provisions of the compatibility
* clause in Article 5 of the EUPL shall not apply.
* If using the Work as, or as part of, a network application, by
* including the attribution notice(s) required under Article 5 of the EUPL
* in the end user terms of the application under an appropriate heading,
* such notice(s) shall fulfill the requirements of that article.
* ********************************************************************* */
const path = require('path');
require(path.join(__dirname, '/../../../deviceDetectionOnPremisePipelineBuilder'));
const ExampleUtils = require(path.join(__dirname, '/../exampleUtils')).ExampleUtils;
const DataExtension = require('fiftyone.devicedetection.shared').dataExtension;
const exampleConstants = require('fiftyone.devicedetection.shared').exampleConstants;
// In this example, by default, the 51degrees "Lite" file needs to be in the
// fiftyone.devicedetection.onpremise/device-detection-cxx/device-detection-data,
// or you may specify another file as a command line parameter.
// Note that the Lite data file is only used for illustration, and has
// limited accuracy and capabilities.
// Find out about the Enterprise data file on our pricing page:
// https://51degrees.com/pricing
const LITE_V_4_1_HASH = '51Degrees-LiteV4.1.hash';
const outputValue = function (name, value) {
// Individual result values have a wrapper called
// `AspectPropertyValue`. This functions similarly to
// a null-able type.
// If the value has not been set then trying to access the
// `value` property will throw an exception.
// `AspectPropertyValue` also includes the `noValueMessage`
// property, which describes why the value has not been set.
return `\n\t${name}: ${value}`;
const analyse = async function (evidence, pipeline, output) {
// FlowData is a data structure that is used to convey
// information required for detection and the results of the
// detection through the pipeline.
// Information required for detection is called "evidence"
// and usually consists of a number of HTTP Header field
// values, in this case represented by a
// Object of header name/value entries.
// list the evidence
let message = 'Input values:';
for (const [key, value] of evidence) {
message += `\n\t${key}: ${value}`;
output.write(message + '\n');
const data = pipeline.createFlowData();
// Add the evidence values to the flow data
evidence.forEach((value, key, map) => {
data.evidence.add(key, value);
await data.process();
message = 'Results:';
// Now that it's been processed, the flow data will have
// been populated with the result. In this case, we want
// information about the device, which we can get by
// asking for the 'device' data.
const device = data.device;
// Display the results of the detection, which are called
// device properties. See the property dictionary at
// https://51degrees.com/developers/property-dictionary
// for details of all available properties.
message += outputValue('Mobile Device', DataExtension.getValueHelper(device, 'ismobile'));
message += outputValue('Platform Name', DataExtension.getValueHelper(device, 'platformname'));
message += outputValue('Platform Version', DataExtension.getValueHelper(device, 'platformversion'));
message += outputValue('Browser Name', DataExtension.getValueHelper(device, 'browsername'));
message += outputValue('Browser Version', DataExtension.getValueHelper(device, 'browserversion'));
message += '\n\n';
const run = async function (dataFile, output) {
// In this example, we use the DeviceDetectionOnPremisePipelineBuilder
// and configure it in code. For more information about
// pipelines in general see the documentation at
// https://51degrees.com/documentation/_concepts__configuration__builders__index.html
dataFile: dataFile,
// We use the low memory profile as its performance is
// sufficient for this example. See the documentation for
// more detail on this and other configuration options:
// https://51degrees.com/documentation/_device_detection__features__performance_options.html
// https://51degrees.com/documentation/_features__automatic_datafile_updates.html
// https://51degrees.com/documentation/_features__usage_sharing.html
performanceProfile: 'LowMemory',
// inhibit sharing usage for this test, usually this
// should be set 'true'
shareUsage: false,
// inhibit auto-update of the data file for this test
autoUpdate: false,
updateOnStart: false,
fileSystemWatcher: false
// carry out some sample detections
for (var values of exampleConstants.defaultEvidenceValues) {
await analyse(values, pipeline, output);
ExampleUtils.checkDataFile(pipeline, dataFile);
// Don't run the server if under TEST
if (process.env.JEST_WORKER_ID === undefined) {
const args = process.argv.slice(2);
// Use the supplied path for the data file or find the lite
// file that is included in the repository.
const dataFile = args.length > 0 ? args[0] : ExampleUtils.findFile(LITE_V_4_1_HASH);
if (dataFile !== undefined) {
run(dataFile, process.stdout);
} else {
console.error('Failed to find a device detection ' +
'data file. Make sure the device-detection-data ' +
'submodule has been updated by running ' +
'`git submodule update --recursive`.');
module.exports = {
run: run