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简化 CountUp.js emitting data instead of update dom (with format)
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// https://github.com/danro/jquery-easing/blob/master/jquery.easing.js | |
const easeOutExpo = (t, b, c, d) => { | |
return c * (-Math.pow(2, -10 * t / d) + 1) * 1024 / 1023 + b; | |
}; | |
const easeInCubic = (t, b, c, d) => { | |
return c * (t /= d) * t * t + b; | |
}; | |
const easeOutCubic = (t, b, c, d) => { | |
return c * ((t = t / d - 1) * t * t + 1) + b; | |
}; | |
const easeOutSine = (t, b, c, d) => { | |
return c * Math.sin(t / d * (Math.PI / 2)) + b; | |
}; | |
export const easeFn = { | |
easeOutExpo, easeInCubic, easeOutCubic, easeOutSine | |
}; | |
// const ensureNumber = (n) => { | |
// return (typeof n === 'number' && !isNaN(n)); | |
// }; | |
class CountUp { | |
constructor({start = 0, end = 1000, duration = 1000, easeFn, handler} = {}) { | |
this.startVal = start; | |
this.endVal = end; | |
this.duration = duration; | |
this.handler = (typeof handler === "function") ? handler : (value) => console.log(value); | |
this.easeFn = (typeof easeFn === "function") ? easeFn : easeOutSine; | |
} | |
start = () => { | |
this.rAF = requestAnimationFrame(this.count); | |
}; | |
update = (value) => { | |
delete this.startTime; | |
if (this.rAF) cancelAnimationFrame(this.rAF); | |
this.startVal = this.frameVal || this.endVal; | |
this.endVal = value; | |
this.start(); | |
}; | |
count = (timestamp) => { | |
if (!this.startTime) { | |
this.startTime = timestamp; | |
} | |
this.timestamp = timestamp; | |
const progress = timestamp - this.startTime; | |
// const remaining = this.duration - progress; // used for `paused` | |
this.frameVal = this.easeFn(progress, this.startVal, this.endVal - this.startVal, this.duration); | |
// don't go past endVal since progress can exceed duration in the last frame | |
this.frameVal = Math.min(this.endVal, this.frameVal); | |
this.frameVal = Math.ceil(this.frameVal); | |
this.handler(this.frameVal); | |
// whether to continue | |
if (progress < this.duration) { | |
this.rAF = requestAnimationFrame(this.count); | |
} | |
}; | |
} | |
export default CountUp; |
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