Getting started with startTransition in React 19

React's Transitions API, introduced in React 18's Concurrent Mode, enhances user experience by preventing expensive UI renders from blocking urgent updates, such as typing in a search bar. This is achieved through the startTransition function, which marks certain updates as non-urgent, allowing more critical updates to take precedence and improving app responsiveness. The API, supported by the useTransition Hook, offers a way to track transition states, providing developers with tools to implement loading indicators during non-blocking transitions. React 19 introduced the capability for the startTransition callback to handle asynchronous operations, simplifying the management of loading and error states. This update allows for smoother app performance during asynchronous tasks, like form submissions, maintaining a responsive UI. The article provides a practical guide on implementing these features in a React project, including a demo app showcasing the transition function's impact on rendering performance.