From c7ea03cad39e0efa05fb9d160e9f3fe5381d61e7 Mon Sep 17 00:00:00 2001
From: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Date: Mon, 17 Aug 2026 09:03:50 +0000
Subject: [PATCH] fix: align README with env-var setup and restore missing
 client-side ID guard

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---
 README.md | 15 +++++++--------
 index.js  |  2 +-
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 11e6a7f..f5aec52 100644
--- a/README.md
+++ b/README.md
@@ -8,16 +8,15 @@ For a sample application demonstrating how to use LaunchDarkly in *server-side*
 
 ## Build instructions
 
-1. Install the LaunchDarkly Client-Side Node.js SDK by running `npm install`
+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.
 
-2. Edit `index.js` and set the value of `environmentId` to your LaunchDarkly client-side ID. If there is an existing boolean feature flag in your LaunchDarkly project that you want to evaluate, set `featureFlagKey` to the flag key.
+    ```bash
+    export LAUNCHDARKLY_CLIENT_SIDE_ID="1234567890abcdef"
+    export LAUNCHDARKLY_FLAG_KEY="my-boolean-flag"
+    ```
 
-```js
-  const environmentId = "1234567890abcdef";
-
-  const featureFlagKey = "my-flag";
-```
+2. Install the LaunchDarkly Client-Side Node.js SDK by running `npm install`
 
 3. Run `node index.js`
 
-You should see the message `"Feature flag '<flag key>' is <true/false> for this user"`.
+You should receive the message "The '<flagKey>' feature flag evaluates to <flagValue>.". The application will run continuously and react to the flag changes in LaunchDarkly.
diff --git a/index.js b/index.js
index 70069da..d5de2e8 100644
--- a/index.js
+++ b/index.js
@@ -1,7 +1,7 @@
 const LaunchDarkly = require('launchdarkly-node-client-sdk');
 
 // Set clientSideId to your LaunchDarkly client-side ID.
-const clientSideId = process.env.LAUNCHDARKLY_CLIENT_SIDE_ID ?? 'your-client-side-id';
+const clientSideId = process.env.LAUNCHDARKLY_CLIENT_SIDE_ID ?? '';
 
 // Set featureFlagKey to the feature flag key you want to evaluate.
 const featureFlagKey = process.env.LAUNCHDARKLY_FLAG_KEY ?? 'sample-feature';