Unit Testing React Components

This topic covers strategies for unit testing React components that use LaunchDarkly feature flags.

Use Case

Test React components that use LaunchDarkly hooks (useFlags, useLDClient, etc.) in isolation without requiring a live connection to LaunchDarkly. This enables:

• Fast, reliable unit tests that don’t depend on network connectivity
• Testing component behavior with specific flag values
• Testing flag-dependent logic and conditional rendering

Challenge

Unlike Jest which has built-in module mocking, Mocha requires external libraries or code patterns to mock the LaunchDarkly React SDK.

Methods

• Mocha - Three approaches for mocking LaunchDarkly in Mocha tests