decentralized-video-chat/public/landing/js/scroll-reveal.js

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1.9 KiB
JavaScript
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2020-03-24 11:20:28 +08:00
;(function () {
'use strict'
const revealEl = document.querySelectorAll('[class*=reveal-]')
let viewportHeight = window.innerHeight
function throttle (delay, fn) {
var lastCall = 0
return function () {
var now = new Date().getTime()
if (now - lastCall < delay) {
return
}
lastCall = now
return fn.apply(void 0, arguments)
}
}
function elementIsVisible (el, offset) {
return (el.getBoundingClientRect().top <= viewportHeight - offset)
}
function revealElements () {
for (let i = 0; i < revealEl.length; i++) {
let el = revealEl[i]
let revealDelay = el.getAttribute('data-reveal-delay')
let revealOffset = (el.getAttribute('data-reveal-offset') ? el.getAttribute('data-reveal-offset') : '200')
let listenedEl = (el.getAttribute('data-reveal-container') ? el.closest(el.getAttribute('data-reveal-container')) : el)
if (elementIsVisible(listenedEl, revealOffset) && !el.classList.contains('is-revealed')) {
if (revealDelay && revealDelay !== 0) {
setTimeout(function () {
el.classList.add('is-revealed')
}, revealDelay)
} else {
el.classList.add('is-revealed')
}
}
}
revealDone()
}
function revealScroll () {
throttle(30, revealElements())
}
function revealResize () {
viewportHeight = window.innerHeight
throttle(30, revealElements())
}
function revealDone () {
if (revealEl.length > document.querySelectorAll('[class*=reveal-].is-revealed').length) return
window.removeEventListener('load', revealElements)
window.removeEventListener('scroll', revealScroll)
window.removeEventListener('resize', revealResize)
}
if (revealEl.length > 0 && document.body.classList.contains('has-animations')) {
window.addEventListener('load', revealElements)
window.addEventListener('scroll', revealScroll)
window.addEventListener('resize', revealResize)
}
}())