51Degrees Device Detection Node.js  4.4

51Degrees Device Detection for Node.js


The device detection data file contains meta data that can provide additional information about the various records in the data model.This example shows how to access this data and display the values available.

To help navigate the data, it's useful to have an understanding of the types of records that are present:

  • Component - A record relating to a major aspect of the entity making a web request. There are currently 4 components: Hardware, Software Platform (OS), Browser and Crawler.
  • Profile - A record containing the details for a specific instance of a component. An example of a hardware profile would be the profile for the iPhone 13. An example of a platform profile would be Android 12.1.0.
  • Property - Each property will have a specific value (or values) for each profile. An example of a hardware property is 'IsMobile'. An example of a browser property is 'BrowserName'.

The example will output each component in turn, with a list of the properties associated with each component. Some of the possible values for each property are also displayed. There are too many profiles to display, so we just list the number of profiles for each component.

Finally, the evidence keys that are accepted by device detection are listed. These are the keys that, when added to the evidence collection in flow data, could have some impact on the result returned by device detection.

This example is available in full on GitHub.

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 2023 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');
const require51 = (requestedPackage) => {
try {
return require(path.join(__dirname, '/../../../node_modules/', requestedPackage));
} catch (e) {
return require(path.join(__dirname, '/../../../../', requestedPackage));
const ExampleUtils = require(path.join(__dirname, '/../exampleUtils')).ExampleUtils;
// 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 truncateToNl = function (string) {
const lines = string.split('\n');
let result = '';
let i = 0;
for (; i < lines.length; i++) {
if (lines[i]) {
result = lines[i];
if (i < lines.length) {
result += ' ...';
return result;
const outputProperties = function (component, output) {
const properties = component.getProperties();
for (const property of properties) {
output.write(`\x1b[31mProperty - ${property.name}\x1b[89m\x1b[0m\n`);
`[Category: ${property.category}](${property.type} - ${property.description})\n`);
if (property.category.toLowerCase() !== 'device metrics') {
let valuesStr = 'Possible values: ';
const values = property.getValues();
let count = 0;
for (const value of values) {
// add value
valuesStr += truncateToNl(value.getName());
// add description if exists
const description = value.getDescription();
if (description) {
valuesStr += `(${description})`;
valuesStr += ',';
if (++count >= 20) {
if (property.getNumberOfValues() > 20) {
valuesStr += ` + ${property.getNumberOfValues() - 20} more ...`;
const outputComponents = function (engine, output) {
const components = engine.components;
for (const value of Object.values(components)) {
output.write(`\x1b[34mComponent - ${value.name}\x1b[89m\x1b[0m\n`);
outputProperties(value, output);
const outputProfileDetails = async function (engine, output) {
const groups = {};
let count = 0;
const profiles = engine.profiles();
for (const profile of profiles) {
if (!groups[profile.component.name]) {
groups[profile.component.name] = 1;
} else {
if (++count % 1000 === 0) {
output.write(`Load ${count} profiles\r`);
output.write(`Load completed: ${count} profiles\n`);
output.write('Profile count:\n');
for (const [key, value] of Object.entries(groups)) {
output.write(`${key} Profiles: ${value}\n`);
const outputEvidenceKeyDetails = async function (engine, output) {
output.write('Accepted evidence keys:\n');
for (const evidence of engine.evidenceKeyFilter.list) {
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
// 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
const device = pipeline.getElement('device');
await outputComponents(device, output);
await outputProfileDetails(device, output);
await outputEvidenceKeyDetails(device, 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`. By default, the \'lite\' file ' +
'included with this code will be used. A different file can be ' +
'specified by supplying the full path as a command line argument');
module.exports = {