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function isPromise(v) {
  return v && typeof v.then === 'function' && Promise.resolve(v) === v && v instanceof Promise
}

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function isNativeClass(v) {
  return !Function.prototype.toString.call(v).indexOf('class')
}

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const elementIsVisibleInViewport = (el, partiallyVisible = false) => {
  const { top, left, bottom, right } = el.getBoundingClientRect();
  const { innerHeight, innerWidth } = window;
  return partiallyVisible
    ? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) &&
        ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth))
    : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth;
};

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const runAsync = fn => {
  const worker = new Worker(
    URL.createObjectURL(new Blob([`postMessage((${fn})());`]), {
      type: 'application/javascript; charset=utf-8'
    })
  );
  return new Promise((res, rej) => {
    worker.onmessage = ({ data }) => {
      res(data), worker.terminate();
    };

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const scrollToTop = () => {
  const c = document.documentElement.scrollTop || document.body.scrollTop;
  if (c > 0) {
    window.requestAnimationFrame(scrollToTop);
    window.scrollTo(0, c - c / 8);
  }
};

const smoothScroll = element =>
  document.querySelector(element).scrollIntoView({

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const throttle = (fn, wait) => {
  let inThrottle, lastFn, lastTime;
  return function() {
    const context = this,
      args = arguments;
    if (!inThrottle) {
      fn.apply(context, args);
      lastTime = Date.now();
      inThrottle = true;
    } else {

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function doSth() {
  if (foo) {
    doSomething()
    return
  }
  if (bar) {
    return bar
  }
}
// ----------

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/*!
 * Determine if an element is in the viewport
 * (c) 2017 Chris Ferdinandi, MIT License, https://gomakethings.com
 * @param  {Node}    elem The element
 * @return {Boolean}      Returns true if element is in the viewport
 */
var isInViewport = function (elem) {
	var distance = elem.getBoundingClientRect();
	return (
		distance.top >= 0 &&

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const context = {
  title: 'hello',
  list: [1, 2, 3]
}

const template = '  \
  <header>${title}</header>  \
  <ul>${list.map(i => `<li>${i}</li>`).join("")}</ul> \
'

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function Parent (name) {
  this.name = name
}
Parent.prototype.getName = function getName () { return this.name }

function Child (name, age) {
  Parent.call(this, name)
  this.age = age
}
Child.prototype = Object.create(Parent.prototype, {