Useful common mathematical functions

mathstuff.js

// Clamp val between min and max
const clamp = (val, min, max) => Math.min(Math.max(min, val), max);

// Supply a value and a range, return val normalized to 0 and 1
const normalize = (val, min, max) => (val - min) / (max - min);

// Shaping Functions ///////////////////////////////////////

// Parabola val between 0 and 1.
// Original function by Iñigo Quiles
const parabola = val => 4.0 * val * (1.0 - val);

// ease-in-out
// val between 0 and 1.
const sigmoid = (val) => 1 / (1 + Math.exp(5+val*(-10)));

// fast-in-out
// val between 0 and 1.
const middle = (val) => {const val2 = val-0.5; return 4*val2*val2*val2+0.5;};

// balanced parabola
(x + 1) * (1 - x)