RxJS

RxJS (Reactive Extensions for JavaScript) is a library for composing asynchronous and event-based programs using observable sequences. It provides core abstractions such as Observables, Subjects, and Operators that allow developers to declaratively handle streams of events and data. In WinCC OA, RxJS is the foundation of the OaRxJsApi — every datapoint subscription (dpConnect) returns an Observable that emits value changes in real time, and operators like map, filter, switchMap, and combineLatest enable powerful data transformations before values reach the UI. RxJS provides the reactive data binding between datapoints and UI components across multiple features including the WebUI Runtime, ULC UX, and the Dashboard. It is loaded once as a Shared Bundle and reused across all standalone pages.