Fix bug where item preview loading indicator sometimes doesn't delay

The loading indicator *should* fade in after two seconds, to avoid a
flash of a loading indicator when the page loads quickly - but in some
circumstances it wouldn't delay:

1. Visit an item page. (It delays correctly the first time!)
2. Click "Infinite Closet", then click a link to another item page.
3. The loading indicator appears immediately, because this time the
   web component JS is already loaded, so the `outfit-layer` elements
   enter `:state(loading)` *immediately*. The element starts at
   `opacity: 1`, and the delay doesn't matter, because it was never at
   anything else.

In this change, we have the `outfit-viewer` web component take on a
`:state(after-first-frame)`, after a `setTimeout(0)` resolves. That
enables the loading state CSS to *never* apply on the first frame, but
then sometimes kick in on the *second* frame, so that the element is
correctly perceived as "transitioning" from hidden to visible, and the
two-second delay will apply.
This commit is contained in:
Emi Matchu 2024-09-06 12:13:10 -07:00
parent 5001a50a60
commit d69c37089e
2 changed files with 19 additions and 6 deletions

View file

@ -21,6 +21,10 @@ class OutfitViewer extends HTMLElement {
this.#setIsPlaying(playPauseToggle.checked); this.#setIsPlaying(playPauseToggle.checked);
this.#setIsPlayingCookie(playPauseToggle.checked); this.#setIsPlayingCookie(playPauseToggle.checked);
}); });
// Tell the CSS our first frame has rendered, which we use for loading
// state transitions.
this.#internals.states.add("after-first-frame");
} }
#setIsPlaying(isPlaying) { #setIsPlaying(isPlaying) {

View file

@ -135,15 +135,24 @@ body.items-show
margin-bottom: .5em margin-bottom: .5em
display: none display: none
// When loading, fade in the loading spinner after a brief delay. (We only // When loading, fade in the loading spinner after a brief delay. We are
// apply the delay here, because fading *out* on load should be instant.) // loading when the <turbo-frame> is busy, or when at least one layer
// We are loading when the <turbo-frame> is busy, or when at least one layer
// is loading. // is loading.
//
// We only apply the delay here, not on the base styles, because fading
// *out* on load should be instant. We also wait for the outfit-viewer to
// execute a `setTimeout(0)`, to make sure we always *start* in the
// non-loading state. This is because it's sometimes possible for the page to
// start with the web component already in `state(loading)`, and we need to
// make sure we *start* in *non-loading* state for the transition delay to
// happen. (This can happen when you Turbo-navigate between multiple items.)
#item-preview[busy] outfit-viewer, outfit-viewer:has(outfit-layer:state(loading)) #item-preview[busy] outfit-viewer, outfit-viewer:has(outfit-layer:state(loading))
cursor: wait cursor: wait
.loading-indicator
opacity: 1 &:state(after-first-frame)
transition-delay: 2s .loading-indicator
opacity: 1
transition-delay: 2s
#item-preview:has(outfit-layer:state(error)) #item-preview:has(outfit-layer:state(error))
outfit-viewer outfit-viewer