Is it possible to create scroll in generic transition Stylus mixin? - css

Question

JavaScript:
const show = entries => entries[0].isIntersecting ? entries[0].classList.remove('is-hidden') : null;
const observer = new IntersectionObserver(show, {threshold:0});
Array.from(document.querySelectorAll('.js-hidden')).forEach(element => observer.observe(element));
I want to play fade in animation when '.js-hidden' class are removed like below... but this code are not working:
HTML:
<div class="my-component js-hidden is-hidden">
<p class="text text-1">Hello</p>
<p class="text text-2">World</p>
</div>
Stylus:
fadeIn(duration=1s, delay=0s) {
opacity: 1;
transition: opacity duration ease delay;
&.is-hidden { // <- yeah, this is wrong... but, any ideas? I want to apply transition both element and pseudo element.
opacity: 0;
}
}
.my-component {
.text,
&::before,
&::after {
fadeIn();
}
.text-2 {
transition-delay: .3s;
}
&::before {
content: 'foo';
transition-delay: .5s;
}
&::after {
content: 'bar';
transition-delay: .7s;
}
}
And, if the fade in elements are more nested?
<div class="my-component js-hidden is-hidden">
<div class="wrapper-1">
<div class="wrapper-2">
<p class="text text-1">Hello</p>
<p class="text text-2">World</p>
</div>
</div>
</div>
I want to apply transition both element and pseudo element. but I don’t know what should I do...
Thanks.
Finally...
Thank you Andy.
Finally I arrived the code below. XD
JavaScript:
const show = entries => entries[0].isIntersecting ? entries[0].target.classList.remove('is-hidden') : null;
const observer = new IntersectionObserver(show, {threshold:0});
Array.from(document.querySelectorAll('.js-hidden')).forEach(element => observer.observe(element));
HTML:
<div class="my-component js-hidden is-hidden">
<p class="text text-1">Hello</p>
<p class="text text-2">World</p>
<p class="text text-3">Hello</p>
<p class="text text-4">World</p>
<p class="text text-5">Hello</p>
<p class="text text-6">World</p>
<p class="text text-7">Hello</p>
<p class="text text-8">World</p>
<p class="text text-9">Hello</p>
</div>
Stylus:
fadeIn(target, duration=1s, delay=0s, property=all, easing=ease) {
{target} {
opacity: 1;
transition: duration property easing delay;
}
&.is-hidden {
{target} {
opacity: 0;
}
}
}
.my-component {
duration = .3s;
delay = 1s;
fadeIn('.text', duration:duration, delay:delay);
fadeIn('&::before', duration:duration, delay:delay);
fadeIn('&::after', duration:duration, delay:delay);
interval = duration;
amount = 9;
for i in 2..amount {
.text-{i} {
transition-delay: (interval * (i - 2) + duration + delay)s;
}
}
&::before {
content: 'FOOOOOOOOOOOOOOO';
transition-delay: (interval * ((amount + 1) - 2) + duration + delay)s;
}
&::after {
content: 'BARRRRRRRRRRRRRR';
transition-delay: (interval * ((amount + 2) - 2) + duration + delay)s;
}
}

Answer 1

First, it seems you're looking for a transition, not an animation. I'm not a Stylus expert, but know IntersectionObserver and CSS pretty well. I have the basic demo working now.
Some notes on the adjusted fadeIn function.
is-hidden is a class that exists in the DOM from the beginning, so cue the transition when it's not there
use a delegate pattern from transitions—that is, have the change in the parent affect the children (don't listen for a class for each child/pseudo element)
fadeIn(duration=1s, delay=0s) {
.text,
&::before,
&::after {
opacity: 0;
transition: 0.5s opacity ease;
}
&:not(.is-hidden) {
.text,
&::before,
&::after {
opacity: 1;
}
}
}
Also, I couldn't get your JavaScript to work due to some errors and rewrote it to suit the demo. Here's the rewritten JavaScript:
const components = document.querySelectorAll(".my-component");
const observer = new IntersectionObserver(components => {
components.forEach(component => {
if (component.intersectionRatio > 0) {
component.target.classList.remove("is-hidden")
} else {
component.target.classList.add("is-hidden")
}
})
});
Array.from(document.querySelectorAll(".js-hidden")).forEach(element =>
observer.observe(element)
);
CodePen Demo