51Degrees Device Detection Node.js  4.4

51Degrees Device Detection for Node.js


This example shows how to use the 51Degrees Cloud service 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 the 51Degrees cloud service
  2. How to pass input data (evidence) to the Pipeline
  3. How to retrieve the results
This example is available in full on GitHub.

To run this example, you will need to create a resource key. The resource key is used as shorthand to store the particular set of properties you are interested in as well as any associated license keys that entitle you to increased request limits and/or paid-for properties.

You can create a resource key using the 51Degrees Configurator.

Required npm Dependencies:

  • fiftyone.pipeline.cloudrequestengine
  • fiftyone.pipeline.core
  • fiftyone.pipeline.engines
  • fiftyone.pipeline.engines.fiftyone
  • fiftyone.devicedetection.cloud


"PipelineOptions": {
"Elements": [
"elementName": "fiftyone.pipeline.cloudrequestengine/cloudRequestEngine",
"elementParameters": {
"resourceKey": "!!YOUR_RESOURCE_KEY!!"
"elementName": "../../../deviceDetectionCloud"
/* *********************************************************************
* 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');
const fs = require('fs');
const { PipelineBuilder } = require('fiftyone.pipeline.core');
const ExampleUtils = require(path.join(__dirname, '/../exampleUtils'));
const exampleConstants = require('fiftyone.devicedetection.shared').exampleConstants;
const OptionsExtension = require('fiftyone.devicedetection.shared').optionsExtension;
const DataExtension = require('fiftyone.devicedetection.shared').dataExtension;
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}: ${value}`;
output.write(message + '\n');
const data = pipeline.createFlowData();
// Add the evidence values to the flow data
evidence.forEach((value, key, map) => {
data.evidence.add(key, value);
await data.process();
message = 'Results:';
// Now that it's been processed, the flow data will have
// been populated with the result. In this case, we want
// information about the device, which we can get by
// asking for the 'device' data.
const device = data.device;
// Display the results of the detection, which are called
// device properties. See the property dictionary at
// https://51degrees.com/developers/property-dictionary
// for details of all available properties.
message += outputValue('Mobile Device', DataExtension.getValueHelper(device, 'ismobile'));
message += outputValue('Platform Name', DataExtension.getValueHelper(device, 'platformname'));
message += outputValue('Platform Version', DataExtension.getValueHelper(device, 'platformversion'));
message += outputValue('Browser Name', DataExtension.getValueHelper(device, 'browsername'));
message += outputValue('Browser Version', DataExtension.getValueHelper(device, 'browserversion'));
message += '\n\n';
const run = async function (options, output) {
const resourceKey = OptionsExtension.getResourceKey(options);
// If we don't have a resource key then log an error
if (!resourceKey) {
'No resource key specified in the configuration file ' +
'\'51d.json\' or the environment variable ' +
`'${ExampleUtils.RESOURCE_KEY_ENV_VAR}'. The 51Degrees cloud ` +
'service is accessed using a \'ResourceKey\'. For more information ' +
'see ' +
'https://51degrees.com/documentation/_info__resource_keys.html. ' +
'A resource key with the properties required by this example can be ' +
'created for free at https://configure.51degrees.com/g3gMZdPY. ' +
'Once complete, populate the config file or environment variable ' +
'mentioned at the start of this message with the key.'
const pipeline = new PipelineBuilder().buildFromConfiguration(options);
// To monitor the pipeline we can put in listeners for various log events.
// Valid types are info, debug, warn, error
pipeline.on('error', console.error);
// carry out some sample detections
for (var values of exampleConstants.defaultEvidenceValues) {
await analyse(values, pipeline, output);
// Don't run the server if under TEST
if (process.env.JEST_WORKER_ID === undefined) {
const args = process.argv.slice(2);
// Use the supplied resource key or try to obtain one
// from the environment variable.
const resourceKey = args.length > 0 ? args[0] : process.env[ExampleUtils.RESOURCE_KEY_ENV_VAR];
// Load the configuration from a config file to a JSON object.
const options = JSON.parse(fs.readFileSync('51d.json'), 'utf8');
const resourceKeyFromConfig = OptionsExtension.getResourceKey(options);
if (!resourceKeyFromConfig || resourceKeyFromConfig.startsWith('!!')) {
OptionsExtension.setResourceKey(options, resourceKey);
run(options, process.stdout);
module.exports = {
run: run