In ReactJS, batching refers to the process of grouping multiple state updates into a single re-render operation to optimize performance. This technique is crucial because re-rendering components can be computationally expensive, particularly in complex applications with a large virtual DOM tree[1].
How Batching Works
When you update the state in a React component using setState, React schedules a re-render. However, instead of re-rendering the component after each individual state update, React groups or "batches" multiple state updates that occur in close succession or within the same event loop tick. This means that the component will only re-render once at the end of the batch, rather than after each state update[1][2].
Evolution of Batching in React
Prior to React 18, batching was limited to state updates that occurred within React event handlers, such as clicks or changes. Updates triggered outside of these handlers, like in promises or setTimeout, were not batched, leading to multiple re-renders and potentially degraded performance[1][4].
With the introduction of React 18, an improved feature called "automatic batching" was implemented. This feature extends batching to virtually all state updates, regardless of where they originate. This includes updates within timeouts, promises, native event handlers, or any other asynchronous events. This enhancement ensures that all state updates within the same event loop tick...
