const faders = document.querySelectorAll('.fade-in');

const appearOptions = {
    threshold: 1
};

const appearOnScroll = new IntersectionObserver( function(entries, appearOnScroll){
    entries.forEach(entry => {
        if(!entry.isIntersecting){  
            return;
        }else{  
            entry.target.classList.add('appear')
            appearOnScroll.unobserve(entry.target)
        }
    })
}, appearOptions);

faders.forEach(fader =>{
    appearOnScroll.observe(fader)
})