Next-tick is a polyfill that provides environment-agnostic nextTick functionality, ensuring consistent behavior across Node.js, modern browsers, and older environments by using the most appropriate method available. It's designed for developers building environment-agnostic modules who need reliable nextTick functionality without worrying about the underlying platform. The library automatically selects the best available option, from process.nextTick in Node.js to queueMicrotask in modern browsers, or falls back to MutationObserver, setImmediate, or setTimeout when necessary.