RolloutCtrl JS Core

Monorepository for the RolloutCtrl JavaScript/TypeScript SDK ecosystem — feature flag and action evaluation platform with local evaluation, metric aggregation, and framework integrations.

Packages

Package	Description
@rolloutctrl/evaluator	Pure, dependency-free evaluation engine. Strategies, segments, rules, percentage rollouts, variant assignment. No networking or I/O.
@rolloutctrl/js-sdk	Browser-focused SDK. Local evaluation, config polling, localStorage persistence, metric aggregation, context resolution.
@rolloutctrl/node-sdk	Server-side Node.js SDK. Local evaluation, config polling, metric aggregation. Uses Node.js APIs (node:events, fetch).
@rolloutctrl/react-sdk	React integration layer. Hooks (useFlag, useVariant, usePermission) and components (Flag, Permission). Thin wrapper over @rolloutctrl/js-sdk.

Examples

• nodejs-express — Express app using @rolloutctrl/node-sdk for feature flag evaluation.
• vite-react-ts — Vite + React + TypeScript app using @rolloutctrl/react-sdk and @rolloutctrl/js-sdk.
• html — Plain HTML page using @rolloutctrl/js-sdk directly from a CDN, no bundler or build step.

Architecture

@rolloutctrl/evaluator  (pure evaluation engine, no dependencies)
        ▲
        │
@rolloutctrl/js-sdk  (browser)     @rolloutctrl/node-sdk  (server)
        ▲
        │
@rolloutctrl/react-sdk  (React hooks & components)

All SDKs perform local evaluation — no HTTP request is made per flag check. Configuration is fetched on startup and polled at a configurable interval. Metrics (flag exposures, strategy matches, variant exposures) are aggregated with deduplication and flushed periodically.

Tooling

• Package manager: Yarn 4 (Berry) with node-modules linker
• Build: tsup (CJS + ESM + dts)
• Test: Jest
• Lint: tsc --noEmit
• Language: TypeScript 5+

Getting Started

# Install dependencies
yarn install

# Build all packages
yarn build

# Run all tests
yarn test

# Lint all packages
yarn lint

Working with a single package

# Build
yarn workspace @rolloutctrl/evaluator build

# Test
yarn workspace @rolloutctrl/js-sdk test

# Watch mode
yarn workspace @rolloutctrl/node-sdk test:watch

License

MIT