Status: Experimental
Feature Management (also called feature toggle, feature flag) makes it easier to enable or disable feature based on specified configuration.
You can install the package via npm:
npm install feature-management
Feature must be declared as a class. Feature flag configuration is then applied by using @FeatureFlag decorator.
@FeatureFlag('production', false)
@FeatureFlag('staging', true)
class HostReport implements IFeature {}Above we've declared a feature called HostReport with feature flag configuration applied for multiple environment. Last step is to initialize feature manager and check if specified feature is enabled or not based on current environment.
if (await featureManager.isEnabled(HostReport)) {
// run this block if enabled
}Strategy helps you enable a feature based on condition defined. You can assign multiple strategies to a feature.
interface FeatureManagerContext {
readonly email?: string;
}
class AllowUsers {
constructor(readonly emails: readonly string[]) {}
}
@StrategyHandler(AllowUsers)
class AllowUsersHandler implements IStrategyHandler {
async evaluate(strategy: AllowUsers, context: FeatureManagerContext) {
if (!context?.email) {
throw new Error('AllowUsers Strategy requires param: email');
}
return strategy.emails.includes(context.email);
}
}Assign strategy to a feature
@FeatureFlag('production', [new AllowUsers(['[email protected]', '[email protected]'])])
@FeatureFlag('staging', true)
class HostReport implements IFeature {}Finally, you can check if feature is enabled using feature manager.
const context = {
email: '[email protected]'
};
if (await featureManager.isEnabled(HostReport, context)) {
// run this block if enabled
}npm run test