LaunchDarkly Sample Client-Side Node.js Application

We've built a simple console application that demonstrates how LaunchDarkly's SDK works. Below, you'll find the basic build procedure, but for more comprehensive instructions, you can visit your Quickstart page.

Please note that this sample application demonstrates how to use the LaunchDarkly Client-Side SDK for Node.js which is designed primarily for use by code that is deployed to an end user, such as in a desktop application or a smart device. It follows the client-side LaunchDarkly model for single-user contexts (much like our mobile or JavaScript SDKs). It is not intended for use in multi-user systems such as web servers and applications.

For a sample application demonstrating how to use LaunchDarkly in server-side Node.js applications, refer to our Server-side Node.js SDK sample application.

Build instructions

1. Set the environment variable LAUNCHDARKLY_CLIENT_SIDE_ID to your LaunchDarkly client-side ID. If there is an existing boolean feature flag in your LaunchDarkly project that you want to evaluate, set LAUNCHDARKLY_FLAG_KEY to the flag key; otherwise, a boolean flag of sample-feature will be assumed.

   export LAUNCHDARKLY_CLIENT_SIDE_ID="1234567890abcdef"
   export LAUNCHDARKLY_FLAG_KEY="my-boolean-flag"

2. Install the LaunchDarkly Client-Side Node.js SDK by running npm install

3. Run node index.js

You should receive the message "The '' feature flag evaluates to .". The application will run continuously and react to the flag changes in LaunchDarkly.