51Degrees Device Detection Node.js  4.1

51Degrees Device Detection for Node.js


This example shows how the 51Degrees device detection engine deals with evidence that does not match any known device. In this scenario, 'HasValue' can be used to check if the property has been populated by the engine. If it hasn't then 'NoValueMessage' can be used to get the reason why.

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.

Expected output:

Is user agent 'This is not a User-Agent' a mobile?
The results contained a null profile for the component which the required property belongs to.
Is user agent 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_2 like Mac OS X) AppleWebKit/604.4.7 (KHTML, like Gecko) Mobile/15C114' a mobile?
/* *********************************************************************
* This Original Work is copyright of 51 Degrees Mobile Experts Limited.
* Copyright 2019 51 Degrees Mobile Experts Limited, 5 Charlotte Close,
* Caversham, Reading, Berkshire, United Kingdom RG4 7BY.
* 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 FiftyOneDegreesDeviceDetection = require((process.env.directory || __dirname) + '/../../');
// Create the device detection pipeline with the desired settings.
// You need to create a resource key at https://configure.51degrees.com
// and paste it into the code, replacing !!YOUR_RESOURCE_KEY!! below.
const myResourceKey = process.env.RESOURCE_KEY || "!!YOUR_RESOURCE_KEY!!";
if (myResourceKey == "!!YOUR_RESOURCE_KEY!!") {
console.log('You need to create a resource key at ' +
'https://configure.51degrees.com and paste it into the code, ' +
'replacing !!YOUR_RESOURCE_KEY!!');
console.log('Make sure to include the ismobile property ' +
'as it is used by this example.');
} else {
// Construct the device detection pipeline using the
// DeviceDetectionPipelineBuilder, passing in your resourceKey.
// The build method completes the pipeline
const pipeline = new FiftyOneDegreesDeviceDetection.DeviceDetectionPipelineBuilder({
resourceKey: myResourceKey
// 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);
// Here we make a function that gets a userAgent as evidence and
// uses the Device Detection Engine to detect if it is a mobile or not
const checkIfMobile = async function (userAgent) {
// Create a FlowData element
// This is used to add evidence and process it through the
// FlowElements in the Pipeline.
const flowData = pipeline.createFlowData();
// Add the User-Agent as evidence
flowData.evidence.add('header.user-agent', userAgent);
// Run process on the flowData (this returns a promise)
await flowData.process();
// Check the ismobile property
// this returns an AspectPropertyValue wrapper
// letting you check if a value is set and if not why not
const ismobile = flowData.device.ismobile;
console.log(`Is user agent '${userAgent}' a mobile?`);
// Check if the result has a meaningful value and output it
if (ismobile.hasValue) {
} else {
// Output why the value isn't meaningful
console.log(' ');
const iPhoneUA = 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_2 like Mac OS X) AppleWebKit/604.4.7 (KHTML, like Gecko) Mobile/15C114';
// This User-Agent is from an iPhone. It should match correctly and be
// identified as a mobile device
const corruptedUA = 'This is not a User-Agent';
// This User-Agent is fake and will not be matched.