Concurrent is one of the most important features in React 18 that has solved an age-old ignored issue. Actually, concurrency is not a feature. It works as the back-stage function that encourages React to create multiple versions of your UI concurrency simultaneously.

React is used to design APIs, and it covers the implementation details from development teams.

They believe that React developers should concentrate on how React features will help them accomplish the user experience they desire for their clients. React will surely help you achieve an amazing user experience.

Albeit Concurrent React is not just about a specific implementation detail, it’s a fundamental React update to its core rendering model, which helps to understand how Concurrency React works in React18.

While not migrating to React 18 or not adding any concurrent features, every update was rendered in a single, synchronous, and uninterrupted transaction. However, the major issue every developer used to face was that with the start of asynchronous rendering transaction, nothing could interrupt it until the users could see the result on the screen. This doesn’t happen every time in concurrent rendering.

React can start rendering an update, pause in the middle, and continue later. It may even abort a rendering that is in process. React ensures to offer a consistent UI even if the render is interrupted. This method allows React to develop new screens in the backend process without blocking the main thread. It means that even if the UI is in the middle of a massive rendering operation, it may respond to user input quickly, resulting in fluid user experience.

Another advantage of concurrent mode is the reusable state. With the help of Concurrent React, React can easily omit the sections of the UI from the screen and add them back while reusing the previous state.

Let’s understand with an example here.

When a user moves to the other tabs and returns to the original tab, React will be able to restore the previous screen in the same state as it was before. However, React 18 is going to have a new component called <Offscreen> to implement this pattern.