45 lines
1.2 KiB
Rust
45 lines
1.2 KiB
Rust
use js_sys::Array;
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use wasm_bindgen::{prelude::Closure, JsCast};
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use web_sys::{Element, IntersectionObserver, IntersectionObserverEntry};
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pub(super) struct IntersectionObserverHandle {
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observer: IntersectionObserver,
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_closure: Closure<dyn FnMut(Array)>,
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}
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impl IntersectionObserverHandle {
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pub fn new<F>(element: &Element, mut callback: F) -> Self
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where
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F: 'static + FnMut(bool),
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{
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let mut skip = true;
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let closure = Closure::new(move |entries: Array| {
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let entry: IntersectionObserverEntry = entries.get(0).unchecked_into();
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let is_intersecting = entry.is_intersecting();
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// skip first intersection
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if skip && is_intersecting {
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skip = false;
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return;
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}
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callback(is_intersecting);
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});
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let observer = IntersectionObserver::new(closure.as_ref().unchecked_ref())
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// we don't provide any `options`
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.expect("Invalid `options`");
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observer.observe(element);
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Self {
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observer,
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_closure: closure,
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}
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}
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}
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impl Drop for IntersectionObserverHandle {
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fn drop(&mut self) {
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self.observer.disconnect()
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}
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}
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