Building a toast component

Sonner is a React toast library downloaded 7M+ times weekly. Its success stems from unique stacking animations using CSS transitions instead of keyframes for smooth interruption, momentum-based swipe gestures, and an Observer Pattern for state management that avoids React Context. Key implementation details include dynamic height calculations for stacking, velocity-based dismissal, tab visibility detection to pause timers, and pointer capture for consistent drag behavior. The library prioritizes developer experience with a simple API and comprehensive documentation.