What are Synthetic Events in React?

Synthetic events in React (SyntheticEvent) are a wrapper for handling native browser events within the React framework. It provides a unified API across browsers, ensuring consistent event handling. Synthetic events primarily achieve the following:

1. Cross-browser compatibility: Synthetic events eliminate inconsistencies across browsers, such as differences in event names and properties that may vary between browsers.
2. Performance optimization: React binds all events to the outermost document using event delegation, rather than directly binding to elements, which helps reduce memory consumption and improve performance.
3. Automatic memory management: React automatically manages memory recycling for synthetic events, avoiding the risk of memory leaks.
4. Extended event properties and methods: Synthetic events provide additional methods and properties, such as stopPropagation() and preventDefault(), which also exist in native events, but synthetic events extend additional functionality, such as persist(), which persists the event beyond pooling (event reuse).

The primary purpose of using synthetic events is to enhance the stability and cross-browser compatibility of React applications, while also optimizing the performance of event handling.