jQuery Easing v1.4.1 converted to TypeScript

jquery.easing.ts

/*
 * jQuery Easing v1.4.1 - http://gsgd.co.uk/sandbox/jquery/easing/
 * Open source under the BSD License.
 * Copyright © 2008 George McGinley Smith
 * All rights reserved.
 * https://raw.github.com/gdsmith/jquery-easing/master/LICENSE
*/

import jQuery from 'jquery';
const $ = jQuery;


declare global {
  interface JQueryStatic {
    easing: {
      jswing(x: number): number
      swing(x: number): number
      easeInQuad(x: number): number
      easeOutQuad(x: number): number
      easeInOutQuad(x: number): number
      easeInCubic(x: number): number
      easeOutCubic(x: number): number
      easeInOutCubic(x: number): number
      easeInQuart(x: number): number
      easeOutQuart(x: number): number
      easeInOutQuart(x: number): number
      easeInQuint(x: number): number
      easeOutQuint(x: number): number
      easeInOutQuint(x: number): number
      easeInSine(x: number): number
      easeOutSine(x: number): number
      easeInOutSine(x: number): number
      easeInExpo(x: number): number
      easeOutExpo(x: number): number
      easeInOutExpo(x: number): number
      easeInCirc(x: number): number
      easeOutCirc(x: number): number
      easeInOutCirc(x: number): number
      easeInElastic(x: number): number
      easeOutElastic(x: number): number
      easeInOutElastic(x: number): number
      easeInBack(x: number): number
      easeOutBack(x: number): number
      easeInOutBack(x: number): number
      easeInBounce(x: number): number
      easeOutBounce(x: number): number
      easeInOutBounce(x: number): number
      [key: string]: (x: number) => number
    }
  }
}

// Preserve the original jQuery "swing" easing as "jswing"
if (typeof $.easing !== 'undefined') {
  $.easing.jswing = $.easing.swing;
}

const pow = Math.pow;
const sqrt = Math.sqrt;
const sin = Math.sin;
const cos = Math.cos;
const PI = Math.PI;
const c1 = 1.70158;
const c2 = c1 * 1.525;
const c3 = c1 + 1;
const c4 = (2 * PI) / 3;
const c5 = (2 * PI)  / 4.5;

// x is the fraction of animation progress, in the range 0..1
function bounceOut(x: number) {
    const n1 = 7.5625;
    const d1 = 2.75;
    if (x < 1 / d1) {
    return n1 * x * x;
  } else if (x < 2 / d1) {
    return n1 * (x -= (1.5 / d1)) * x + .75;
  } else if (x < 2.5 / d1) {
    return n1 * (x -= (2.25 / d1)) * x + .9375;
  } else {
    return n1 * (x -= (2.625 / d1)) * x + .984375;
  }
}

$.extend($.easing,
{
  swing(x: number) {
    return $.easing.easeOutQuad(x);
  },
  easeInQuad(x: number) {
    return x * x;
  },
  easeOutQuad(x: number) {
    return 1 - (1 - x) * (1 - x);
  },
  easeInOutQuad(x: number) {
    return x < 0.5 ?
      2 * x * x :
      1 - pow(-2 * x + 2, 2) / 2;
  },
  easeInCubic(x: number) {
    return x * x * x;
  },
  easeOutCubic(x: number) {
    return 1 - pow(1 - x, 3);
  },
  easeInOutCubic(x: number) {
    return x < 0.5 ?
      4 * x * x * x :
      1 - pow(-2 * x + 2, 3) / 2;
  },
  easeInQuart(x: number) {
    return x * x * x * x;
  },
  easeOutQuart(x: number) {
    return 1 - pow(1 - x, 4);
  },
  easeInOutQuart(x: number) {
    return x < 0.5 ?
      8 * x * x * x * x :
      1 - pow(-2 * x + 2, 4) / 2;
  },
  easeInQuint(x: number) {
    return x * x * x * x * x;
  },
  easeOutQuint(x: number) {
    return 1 - pow(1 - x, 5);
  },
  easeInOutQuint(x: number) {
    return x < 0.5 ?
      16 * x * x * x * x * x :
      1 - pow(-2 * x + 2, 5) / 2;
  },
  easeInSine(x: number) {
    return 1 - cos(x * PI / 2);
  },
  easeOutSine(x: number) {
    return sin(x * PI / 2);
  },
  easeInOutSine(x: number) {
    return -(cos(PI * x) - 1) / 2;
  },
  easeInExpo(x: number) {
    return x === 0 ? 0 : pow(2, 10 * x - 10);
  },
  easeOutExpo(x: number) {
    return x === 1 ? 1 : 1 - pow(2, -10 * x);
  },
  easeInOutExpo(x: number) {
    return x === 0 ? 0 : x === 1 ? 1 : x < 0.5 ?
      pow(2, 20 * x - 10) / 2 :
      (2 - pow(2, -20 * x + 10)) / 2;
  },
  easeInCirc(x: number) {
    return 1 - sqrt(1 - pow(x, 2));
  },
  easeOutCirc(x: number) {
    return sqrt(1 - pow(x - 1, 2));
  },
  easeInOutCirc(x: number) {
    return x < 0.5 ?
      (1 - sqrt(1 - pow(2 * x, 2))) / 2 :
      (sqrt(1 - pow(-2 * x + 2, 2)) + 1) / 2;
  },
  easeInElastic(x: number) {
    return x === 0 ? 0 : x === 1 ? 1 :
      -pow(2, 10 * x - 10) * sin((x * 10 - 10.75) * c4);
  },
  easeOutElastic(x: number) {
    return x === 0 ? 0 : x === 1 ? 1 :
      pow(2, -10 * x) * sin((x * 10 - 0.75) * c4) + 1;
  },
  easeInOutElastic(x: number) {
    return x === 0 ? 0 : x === 1 ? 1 : x < 0.5 ?
      -(pow(2, 20 * x - 10) * sin((20 * x - 11.125) * c5)) / 2 :
      pow(2, -20 * x + 10) * sin((20 * x - 11.125) * c5) / 2 + 1;
  },
  easeInBack(x: number) {
    return c3 * x * x * x - c1 * x * x;
  },
  easeOutBack(x: number) {
    return 1 + c3 * pow(x - 1, 3) + c1 * pow(x - 1, 2);
  },
  easeInOutBack(x: number) {
    return x < 0.5 ?
      (pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2 :
      (pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
  },
  easeInBounce(x: number) {
    return 1 - bounceOut(1 - x);
  },
  easeOutBounce: bounceOut,
  easeInOutBounce(x: number) {
    return x < 0.5 ?
      (1 - bounceOut(1 - 2 * x)) / 2 :
      (1 + bounceOut(2 * x - 1)) / 2;
  }
});