A bunch of easing functions

easing-functions.js

function linear (m) {
  return m
}

function power1In (m) {
  return -Math.cos(m * (Math.PI / 2)) + 1
}

function power1Out (m) {
  return Math.sin(m * (Math.PI / 2))
}

function power1InOut (m) {
  return -0.5 * (Math.cos(Math.PI * m) - 1)
}

function power2In (m) {
  return m * m
}

function power2Out (m) {
  return m * (2 - m)
}

function power2InOut (m) {
  return m < 0.5 ? 2 * m * m : -1 + (4 - 2 * m) * m
}

function power3In (m) {
  return m * m * m
}

function power3Out (m) {
  return (--m) * m * m + 1
}

function power3InOut (m) {
  return m < 0.5 ? 4 * m * m * m : (m - 1) * (2 * m - 2) * (2 * m - 2) + 1
}

function power4In (m) {
  return m * m * m * m
}

function power4Out (m) {
  return 1 - (--m) * m * m * m
}

function power4InOut (m) {
  return m < 0.5 ? 8 * m * m * m * m : 1 - 8 * (--m) * m * m * m
}

function power5In (m) {
  return m * m * m * m * m
}

function power5Out (m) {
  return 1 + (--m) * m * m * m * m
}

function power5InOut (m) {
  return m < 0.5 ? 16 * m * m * m * m * m : 1 + 16 * (--m) * m * m * m * m
}

function expoIn (m) {
  return (m === 0) ? 0 : Math.pow(2, 10 * (m - 1))
}

function expoOut (m) {
  return (m === 1) ? 1 : -Math.pow(2, -10 * m) + 1
}

function expoInOut (m) {
  return (m === 0)
    ? 0
    : (m === 1)
      ? 1
      : ((m /= 0.5) < 1)
        ? (0.5 * Math.pow(2, 10 * (m - 1)))
        : (0.5 * (-Math.pow(2, -10 * --m) + 2))
}

function circIn (m) {
  return -(Math.sqrt(1 - (m * m)) - 1)
}

function circOut (m) {
  return Math.sqrt(1 - Math.pow((m - 1), 2))
}

function circInOut (m) {
  return ((m /= 0.5) < 1)
    ? (-0.5 * (Math.sqrt(1 - m * m) - 1))
    : (0.5 * (Math.sqrt(1 - (m -= 2) * m) + 1))
}

function backIn (m) {
  const s = 1.70158

  return m * m * ((s + 1) * m - s)
}

function backOut (m) {
  const s = 1.70158

  return (m = m - 1) * m * ((s + 1) * m + s) + 1
}

function backInOut (m) {
  const r = 1.525
  let s = 1.70158

  return (m /= 0.5) < 1
    ? (0.5 * (m * m * (((s *= r) + 1) * m - s)))
    : (0.5 * ((m -= 2) * m * (((s *= r) + 1) * m + s) + 2))
}

function elastic (m) {
  return -1 * Math.pow(4, -8 * m) * Math.sin((m * 6 - 1) * (2 * Math.PI) / 2) + 1
}

function swingFromTo (m) {
  const r = 1.525
  let s = 1.70158

  return (m /= 0.5) < 1
    ? (0.5 * (m * m * (((s *= r) + 1) * m - s)))
    : (0.5 * ((m -= 2) * m * (((s *= r) + 1) * m + s) + 2))
}

function swingFrom (m) {
  const s = 1.70158

  return m * m * ((s + 1) * m - s)
}

function swingTo (m) {
  const s = 1.70158

  return (m -= 1) * m * ((s + 1) * m + s) + 1
}

function bounce (m) {
  const q = 2.25, u = 0.984375, v = 7.5625, w = 0.9375, x = 2.75, y = 2.625, z = 0.75

  return (m < 1 / x)
    ? (v * m * m)
    : (m < 2 / x)
      ? (v * (m -= 1.5 / x) * m + z)
      : (m < 2.5 / x)
        ? (v * (m -= q / x) * m + w)
        : (v * (m -= y / x) * m + u)
}

function bouncePast (m) {
  const q = 2.25, u = 0.984375, v = 7.5625, w = 0.9375, x = 2.75, y = 2.625, z = 0.75

  return (m < 1 / x)
    ? (v * m * m)
    : (m < 2 / x)
      ? (2 - (v * (m -= 1.5 / x) * m + z))
      : (m < 2.5 / x)
        ? (2 - (v * (m -= q / x) * m + w))
        : (2 - (v * (m -= y / x) * m + u))
}