deepstream.io JavaScript Client

The `deepstream.io-client-js` library is the official JavaScript client for connecting to a deepstream.io server, enabling real-time data synchronization, remote procedure calls (RPCs), and publish/subscribe messaging patterns. The current major stable version, `4.0.0`, brought significant advancements over previous versions. This includes a new binary protocol for improved efficiency, full TypeScript declaration files for enhanced developer experience, and a comprehensive shift to promise-based APIs, leveraging `async/await` for asynchronous operations. A key differentiator is its robust offline support, allowing data to be stored client-side using IndexedDB and synchronized upon reconnection. While a precise release cadence isn't explicitly defined, the jump to `v4.0.0` indicates active and substantial development. It's designed for high-performance, real-time applications, offering an opinionated, stateful data synchronization model that distinguishes it from simpler WebSocket libraries or REST-based solutions.