elastic-in-out.js

function elasticInOut(t) {
  return t < 0.5
    ? 0.5 * Math.sin(+13.0 * Math.PI/2 * 2.0 * t) * Math.pow(2.0, 10.0 * (2.0 * t - 1.0))
    : 0.5 * Math.sin(-13.0 * Math.PI/2 * ((2.0 * t - 1.0) + 1.0)) * Math.pow(2.0, -10.0 * (2.0 * t - 1.0)) + 1.0
}

module.exports = elasticInOut