Node.js SDK For Harness Feature Flags
Use this README to get started with our Feature Flags (FF) SDK for Node.js. This guide outlines the basics of getting
started with the SDK and provides a full code sample for you to try out.
This sample doesn't include configuration options, for in depth steps and configuring the SDK, for example, disabling
streaming or using our Relay Proxy, see the Node.js SDK Reference.
Requirements
To use this SDK, make sure you’ve:
- Installed Node.js v12 or a newer version
To follow along with our test code sample, make sure you’ve:
Installing the SDK
The first step is to install the FF SDK as a dependency in your application. To install using npm, use:
npm install @harnessio/ff-nodejs-server-sdk
Or to install with yarn, use:
yarn add @harnessio/ff-nodejs-server-sdk
Code Sample
The following is a complete code example that you can use to test the harnessappdemodarkmode
Flag you created on the
Harness Platform. When you run the code it will:
- Connect to the FF service.
- Report the value of the Flag every 10 seconds until the connection is closed.
- Listen for when the
harnessappdemodarkmode
Flag is toggled on or off on the Harness Platform and report the new value.
const { Client, Event } = require('@harnessio/ff-nodejs-server-sdk');
(async () => {
const apiKey = 'YOUR_FF_SDK_KEY';
const flagName = 'harnessappdemodarkmode';
console.log('Harness SDK Getting Started');
const client = new Client(apiKey);
const target = {
identifier: 'nodeserversdk',
name: 'NodeServerSDK',
attributes: {
location: 'emea',
},
};
await client.waitForInitialization();
try {
setInterval(async () => {
const value = await client.boolVariation(flagName, target, false);
console.log('Flag variation:', value);
}, 10000);
client.on(Event.CHANGED, async (flagIdentifier) => {
const value = await client.boolVariation(flagIdentifier, target, false);
console.log(`${flagIdentifier} changed: ${value}`);
});
} catch (e) {
console.error('Error:', e);
}
})();
Running the example
To run the example, execute your script:
node example.js
When you're finished you can exit the example by stopping the process using control-c.
Additional Reading
For further examples and config options, see the Node.js SDK Reference and the test Node.js project.
For more information about Feature Flags, see our Feature Flags documentation.