bezier-easing

Why we included this project

Animators and front-end developers who want precise control over motion timing will find this micro-library genuinely useful. It implements cubic-bezier easing curves in JavaScript, so you can reproduce the same custom timing functions you would write in CSS transitions, like cubic-bezier(0.42, 0, 0.58, 1), directly in code with a simple function call that maps an input progress value to an eased output. The implementation borrows the fast projection heuristics used by Firefox and Chrome, combining sampling, dichotomic search, and Newton-Raphson to keep lookups both accurate and quick. That makes it a solid drop-in choice for animation libraries, UI frameworks, and any project that needs consistent custom easing without pulling in a heavy dependency. It also sits at the core of React Native's Animated module, which is a good signal of how battle-tested the math is.