optimizely-exp-feature-flags

Optimizely Feature Flags Agent

Analyze feature flag implementation, typed accessors, and flag lifecycle management.

Analysis Areas

1. Missing Default Values

FF-001: Feature Flag Without Default (Warning)

Flags should have defaults for SDK failures:

Grep: isFeatureEnabled\(.*\)(?!\s*\?\?)
Grep: decide\(.*\)\.enabled(?!\s*\?\?)

Bad Pattern:

// No fallback if SDK fails!
const isEnabled = optimizely.isFeatureEnabled('new_feature', userId);
if (isEnabled) {
  showNewFeature();
}

Good Pattern:

// With default value
const isEnabled = optimizely.isFeatureEnabled('new_feature', userId) ?? false;

// Or with try/catch
let isEnabled = false;
try {
  isEnabled = optimizely.isFeatureEnabled('new_feature', userId);
} catch {
  console.warn('Feature flag check failed, using default');
}

2. Typed Feature Variables

FF-002: No Typed Feature Variables (Warning)

Feature variables should use typed accessors:

Grep: getFeatureVariable\(
Grep: getFeatureVariableString\(
Grep: getFeatureVariableInteger\(
Grep: getFeatureVariableDouble\(
Grep: getFeatureVariableBoolean\(
Grep: getFeatureVariableJSON\(

Bad Pattern:

// Generic accessor - type unsafe
const discount = optimizely.getFeatureVariable('pricing', 'discount', userId);
// discount is string | number | boolean | object | null

Good Pattern:

// Typed accessor
const discount = optimizely.getFeatureVariableDouble('pricing', 'discount', userId);
// discount is number | null

// Or with modern decide API
const decision = optimizely.decide('pricing', userId);
const discount = decision.variables.discount as number;

3. Render Loop Evaluation

FF-003: Flag Evaluated in Render Loop (Warning)

Flags should not be evaluated on every render:

Grep: function.*\{[\s\S]*?isFeatureEnabled
Grep: return.*isFeatureEnabled

Bad Pattern:

function Component() {
  // Called on EVERY render!
  const showBanner = optimizely.isFeatureEnabled('banner', userId);

  return showBanner ? <Banner /> : null;
}