41 lines
1.2 KiB
JavaScript
41 lines
1.2 KiB
JavaScript
// https://css-tricks.com/styling-based-on-scroll-position/
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// script to detect the scroll position and then call for it in css
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// The debounce function receives our function as a parameter
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const debounce = (fn) => {
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// This holds the requestAnimationFrame reference, so we can cancel it if we wish
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let frame;
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// The debounce function returns a new function that can receive a variable number of arguments
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return (...params) => {
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// If the frame variable has been defined, clear it now, and queue for next frame
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if (frame) {
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cancelAnimationFrame(frame);
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}
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// Queue our function call for the next frame
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frame = requestAnimationFrame(() => {
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// Call our function and pass any params we received
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fn(...params);
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});
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}
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};
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// Reads out the scroll position and stores it in the data attribute
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// so we can use it in our stylesheets
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const storeScroll = () => {
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document.documentElement.dataset.scroll = window.scrollY;
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}
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// Listen for new scroll events, here we debounce our `storeScroll` function
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document.addEventListener('scroll', debounce(storeScroll), { passive: true });
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// Update scroll position for first time
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storeScroll();
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