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Created August 28, 2017 13:52
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rAF tutorial: boilerplate code
"use strict";
// animation utils
// ===============
const trackTime = id => {
const [entry] = performance.getEntriesByName(id);
if (!entry) {
performance.mark(id);
return 0;
}
return performance.now() - entry.startTime;
};
const delay = (callback, duration) => {
const tick = () =>
getProgress(time) < 1 ? requestAnimationFrame(tick) : callback();
const time = {
duration,
id: requestAnimationFrame(tick)
};
};
const getProgress = ({duration = 1000, id}) => {
const progress = duration ? Math.min(trackTime(id) / duration, 1) : 1;
if (progress == 1) performance.clearMarks(id);
return progress;
};
const getCurrentValue = ({from = 0, to, easing}) =>
from + (to - from) * easing;
// easing equations
// ================
const ease = {
in: {
cubic: progress => Math.pow(progress, 3),
quartic: progress => Math.pow(progress, 4),
quintic: progress => Math.pow(progress, 5),
exponential: progress => progress > 0 ? Math.pow(1024, progress - 1) : 0,
circular: progress => 1 - Math.sqrt(1 - Math.pow(progress, 2)),
elastic: progress => {
if (progress == 0) return 0;
if (progress == 1) return 1;
return -Math.pow(2, 10 * (progress - 1)) * Math.sin((progress - 1.1) * 5 * Math.PI);
}
},
out: {
cubic: progress => Math.pow(--progress, 3) + 1,
quartic: progress => 1 - Math.pow(--progress, 4),
quintic: progress => Math.pow(--progress, 5) + 1,
exponential: progress => progress < 1 ? 1 - Math.pow(2, -10 * progress) : 1,
circular: progress => Math.sqrt(1 - Math.pow(--progress, 2)),
elastic: progress => {
if (progress == 0) return 0;
if (progress == 1) return 1;
return Math.pow(2, -10 * progress) * Math.sin((progress - .1) * 5 * Math.PI) + 1;
}
},
inOut: {
cubic: progress =>
(progress *= 2) < 1
? .5 * Math.pow(progress, 3)
: .5 * ((progress -= 2) * Math.pow(progress, 2) + 2),
quartic: progress =>
(progress *= 2) < 1
? .5 * Math.pow(progress, 4)
: -.5 * ((progress -= 2) * Math.pow(progress, 3) - 2),
quintic: progress =>
(progress *= 2) < 1
? .5 * Math.pow(progress, 5)
: .5 * ((progress -= 2) * Math.pow(progress, 4) + 2),
exponential: progress => {
if (progress == 0) return 0;
if (progress == 1) return 1;
return (progress *= 2) < 1
? .5 * Math.pow(1024, progress - 1)
: .5 * (-Math.pow(2, -10 * (progress - 1)) + 2);
},
circular: progress =>
(progress *= 2) < 1
? -.5 * (Math.sqrt(1 - Math.pow(progress, 2)) - 1)
: .5 * (Math.sqrt(1 - (progress -= 2) * progress) + 1),
elastic: progress => {
if (progress == 0) return 0;
if (progress == 1) return 1;
progress *= 2;
const sin = Math.sin((progress - 1.1) * 5 * Math.PI);
return progress < 1
? -.5 * Math.pow(2, 10 * (progress - 1)) * sin
: .5 * Math.pow(2, -10 * (progress - 1)) * sin + 1;
}
}
};
// animation example
// =================
const animate = () => {
const tick = () => {
const progress = getProgress(animation);
if (progress < 1) requestAnimationFrame(tick);
// 1. write your animation logic -----------------------------------------
const easing = ease.out.circular(progress);
const value = getCurrentValue({from: 0, to: 800, easing});
document.body.firstElementChild.style.transform = `translate(${value}px)`;
};
const animation = {
// 2. optionally specify a duration (defaults to 1s) ---------------------
duration: 2000,
id: requestAnimationFrame(tick)
};
};
// 3. optionally set a timeout -----------------------------------------------
delay(animate, 500);
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