coreybutler/fsevents

fsevents is a tool that lets Mac applications built with Node.js listen for changes to files and folders. Instead of constantly checking whether something has been modified, your program gets an automatic heads-up the moment the operating system notices a file was created, edited, deleted, or moved. This makes file-watching features feel instant and responsive. Under the hood, it taps into a built-in macOS feature called FSEvents, which already knows about every file change happening on your computer. The library connects Node.js directly to that system, so when a file changes, your code receives a notification with details about what happened and where. You write a small bit of code that says "watch this folder," and then you get a callback each time something changes, along with helpful context about the event. Developers who build tools like text editors, file sync apps, or build systems would find this useful. For example, if you're making a development tool that automatically refreshes whenever you save a file, this library lets your program react the instant the save happens. It's faster and lighter than alternative approaches that repeatedly scan folders looking for changes. The project describes itself as a low-level library, meaning it handles the core plumbing but doesn't try to do everything. It works only on macOS, so it's not a fit if you need your app to watch files on Windows or Linux. For that cross-platform scenario, the README points readers toward a companion project called Chokidar that uses this library under the hood while adding broader compatibility.