ui/node_modules/@melt-ui/svelte/dist/builders/scroll-area/helpers.js

import { noop, safeOnDestroy, clamp } from '../../internal/helpers/index.js';
export function debounceCallback(cb, delay) {
    let debounceTimer = 0;
    safeOnDestroy(() => {
        clearTimeout(debounceTimer);
    });
    return () => {
        window.clearTimeout(debounceTimer);
        debounceTimer = window.setTimeout(cb, delay);
    };
}
export function resizeObserver(node, handleResize) {
    let animationFrame = 0;
    const observer = new ResizeObserver(() => {
        cancelAnimationFrame(animationFrame);
        animationFrame = requestAnimationFrame(handleResize);
    });
    observer.observe(node);
    return () => {
        window.cancelAnimationFrame(animationFrame);
        observer.unobserve(node);
    };
}
// Custom scroll handler to avoid scroll-linked effects
// https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Scroll-linked_effects
export function addUnlinkedScrollListener(node, handler = noop) {
    let prevPosition = { left: node.scrollLeft, top: node.scrollTop };
    let rAF = 0;
    (function loop() {
        const position = { left: node.scrollLeft, top: node.scrollTop };
        const isHorizontalScroll = prevPosition.left !== position.left;
        const isVerticalScroll = prevPosition.top !== position.top;
        if (isHorizontalScroll || isVerticalScroll)
            handler();
        prevPosition = position;
        rAF = window.requestAnimationFrame(loop);
    })();
    return () => window.cancelAnimationFrame(rAF);
}
export function isScrollingWithinScrollbarBounds(scrollPos, maxScrollPos) {
    return scrollPos > 0 && scrollPos < maxScrollPos;
}
// https://github.com/tmcw-up-for-adoption/simple-linear-scale/blob/master/index.js
function linearScale(input, output) {
    return (value) => {
        if (input[0] === input[1] || output[0] === output[1])
            return output[0];
        const ratio = (output[1] - output[0]) / (input[1] - input[0]);
        return output[0] + ratio * (value - input[0]);
    };
}
export function toInt(value) {
    return value ? parseInt(value, 10) : 0;
}
export function getThumbRatio(viewportSize, contentSize) {
    const ratio = viewportSize / contentSize;
    return isNaN(ratio) ? 0 : ratio;
}
export function getThumbSize(sizes) {
    const ratio = getThumbRatio(sizes.viewport, sizes.content);
    const scrollbarPadding = sizes.scrollbar.paddingStart + sizes.scrollbar.paddingEnd;
    const thumbSize = (sizes.scrollbar.size - scrollbarPadding) * ratio;
    // minimum of 18 matches macOS minimum
    return Math.max(thumbSize, 18);
}
export function getScrollPositionFromPointer(pointerPos, pointerOffset, sizes, dir = 'ltr') {
    const thumbSizePx = getThumbSize(sizes);
    const thumbCenter = thumbSizePx / 2;
    const offset = pointerOffset || thumbCenter;
    const thumbOffsetFromEnd = thumbSizePx - offset;
    const minPointerPos = sizes.scrollbar.paddingStart + offset;
    const maxPointerPos = sizes.scrollbar.size - sizes.scrollbar.paddingEnd - thumbOffsetFromEnd;
    const maxScrollPos = sizes.content - sizes.viewport;
    const scrollRange = dir === 'ltr' ? [0, maxScrollPos] : [maxScrollPos * -1, 0];
    const interpolate = linearScale([minPointerPos, maxPointerPos], scrollRange);
    return interpolate(pointerPos);
}
export function getThumbOffsetFromScroll(scrollPos, sizes, dir = 'ltr') {
    const thumbSizePx = getThumbSize(sizes);
    const scrollbarPadding = sizes.scrollbar.paddingStart + sizes.scrollbar.paddingEnd;
    const scrollbar = sizes.scrollbar.size - scrollbarPadding;
    const maxScrollPos = sizes.content - sizes.viewport;
    const maxThumbPos = scrollbar - thumbSizePx;
    const [scrollClampMin, scrollClampMax] = dir === 'ltr' ? [0, maxScrollPos] : [maxScrollPos * -1, 0];
    const scrollWithoutMomentum = clamp(scrollClampMin, scrollPos, scrollClampMax);
    const interpolate = linearScale([0, maxScrollPos], [0, maxThumbPos]);
    return interpolate(scrollWithoutMomentum);
}