Reactivity in Programming

Reactivity in programming automatically updates systems based on data changes, treating data as streams of events ordered in time. Reactive programming prioritizes managing data flows and their relationships. From a user perspective, reactivity means instant interface responses to actions. For developers, it involves automatically updating data-dependent values, unlike traditional static calculations. Push reactivity immediately pushes data changes to all subscribers, while pull reactivity updates only when requested. Push reactivity, often implemented with libraries like RxJS, can lead to performance issues with frequent updates and complex calculations. Pull reactivity, exemplified by pull-to-refresh patterns, can be less efficient due to system-wide updates for each notification. Reactive programming, building on reactivity concepts, manages asynchronous data flows, enabling transformations and filtering. It simplifies complex systems by focusing on data relationships rather than direct action descriptions, often used in modern frontend applications. Reactive programming blends with other paradigms, with functional reactive programming being particularly prevalent.