How to Fix `e.target.closest is not a function` Error with JavaScript mouseleave Events

Encountered the "Uncaught TypeError: e.target.closest is not a function" error when using JavaScript's `mouseleave` event? This article dives into the root cause—when an event listener is bound to the `document`, the event target `e.target` isn't always a DOM element. It provides three effective solutions: type checking (recommended), try-catch blocks, and direct event binding to help you write more robust and reliable frontend code.