Feature flags or feature toggles are powerful techniques that enable developers to control the release and activation of new features in their applications. By using feature flags in your JavaScript CI/CD workflow, you can easily manage and deploy new features with minimal risk and impact on your users.

In this blog post, we will explore how to implement feature flags in a JavaScript CI/CD workflow using a popular JavaScript library called launchdarkly-js-client-sdk.

Table of Contents

• What are feature flags?
• Why use feature flags in your CI/CD workflow?
• Implementing feature flags in your JavaScript CI/CD workflow
  • Step 1: Install the launchdarkly-js-client-sdk library
  • Step 2: Create feature flags in LaunchDarkly
  • Step 3: Integrate feature flags in your JavaScript code
  • Step 4: Enable feature flags in your CI/CD pipeline
• Conclusion

What are feature flags?

Feature flags, also known as feature toggles or feature switches, are software development techniques that allow developers to enable or disable certain features or code blocks in an application. This toggle can be controlled remotely so that new features can be tested and released in a controlled manner.

Why use feature flags in your CI/CD workflow?

Using feature flags in your CI/CD workflow brings several benefits:

• Risk management: Feature flags enable you to quickly and easily turn off a feature that is causing issues or not performing as expected.
• Testing in production: By toggling feature flags for a subset of users, you can test new features or changes in a real production environment without impacting all users.
• Phased releases: Feature flags allow you to gradually roll out new features to a select group of users before releasing to everyone, reducing the risk of negative impact on your user base.
• Continuous integration: Feature flags facilitate the continuous integration approach by allowing developers to merge their code changes to the main branch without necessarily releasing the new feature to all users immediately.

Implementing feature flags in your JavaScript CI/CD workflow

Step 1: Install the launchdarkly-js-client-sdk library

To get started, you need to install the launchdarkly-js-client-sdk library in your JavaScript project. You can do this by running the following command:

npm install launchdarkly-js-client-sdk

Step 2: Create feature flags in LaunchDarkly

Next, you need to create feature flags in the LaunchDarkly dashboard. Feature flags define the rules and conditions that determine when a feature should be enabled or disabled. Make sure to give your feature flags meaningful names and descriptions to easily identify them in your code.

Step 3: Integrate feature flags in your JavaScript code

Once you have created your feature flags, you can integrate them into your JavaScript code. The launchdarkly-js-client-sdk provides a simple and intuitive API for working with feature flags. You can import it into your code and use it to check the state of a feature flag and conditionally execute code based on its status.

Here’s an example of how to use the launchdarkly-js-client-sdk to check the state of a feature flag:

import { initialize, variation } from 'launchdarkly-js-client-sdk';

// Initialize the SDK with your LaunchDarkly SDK key
initialize('your-sdk-key');

// Check the state of a feature flag
const featureFlagState = variation('feature-flag-key', false);

if (featureFlagState) {
  // Execute some code only if the feature flag is enabled
  // ...
} else {
  // Execute some fallback code if the feature flag is disabled
  // ...
}

Step 4: Enable feature flags in your CI/CD pipeline

To enable feature flags in your CI/CD pipeline, you need to configure your deployment process to fetch the latest state of feature flags from LaunchDarkly at runtime. This ensures that the feature flags are always up to date and can be controlled without requiring a new deployment.

You can achieve this by setting up environment variables or configuration files that store the relevant feature flag keys and values. These variables can then be accessed by your JavaScript code during runtime.

Conclusion

Implementing feature flags in your JavaScript CI/CD workflow is an effective way to manage and release new features with minimal risk. By using the launchdarkly-js-client-sdk library, you can easily integrate feature flags into your JavaScript code and enable a range of powerful feature management capabilities. So start using feature flags in your CI/CD workflow today and take control of your feature releases.