framer-motion/dist/es/value/use-scroll.mjs

A simple and powerful JavaScript animation library

"use client";
import { microtask, cancelMicrotask, supportsViewTimeline, supportsScrollTimeline, motionValue } from 'motion-dom';
import { invariant } from 'motion-utils';
import { useRef, useCallback, useEffect } from 'react';
import { scroll } from '../render/dom/scroll/index.mjs';
import { offsetToViewTimelineRange } from '../render/dom/scroll/utils/offset-to-range.mjs';
import { useConstant } from '../utils/use-constant.mjs';
import { useIsomorphicLayoutEffect } from '../utils/use-isomorphic-effect.mjs';

const createScrollMotionValues = () => ({
    scrollX: motionValue(0),
    scrollY: motionValue(0),
    scrollXProgress: motionValue(0),
    scrollYProgress: motionValue(0),
});
const isRefPending = (ref) => {
    if (!ref)
        return false;
    return !ref.current;
};
function makeAccelerateConfig(axis, options, container, target) {
    return {
        // Refs attach child-first; defer so target.current is populated
        // before scroll() reads it.
        factory: (animation) => {
            let cleanup;
            const start = () => {
                // A provided ref may be hydrated by an effect declared after
                // useScroll (or in a parent). Don't attach to the window
                // scroll in the meantime — that result gets cached and would
                // permanently mistrack. Wait until the ref resolves.
                if (isRefPending(container) || isRefPending(target)) {
                    microtask.read(start);
                    return;
                }
                cleanup = scroll(animation, {
                    ...options,
                    axis,
                    container: container?.current || undefined,
                    target: target?.current || undefined,
                });
            };
            microtask.read(start);
            return () => {
                cancelMicrotask(start);
                cleanup?.();
            };
        },
        times: [0, 1],
        keyframes: [0, 1],
        ease: (v) => v,
        duration: 1,
    };
}
function canAccelerateScroll(target, offset) {
    if (typeof window === "undefined")
        return false;
    return target
        ? supportsViewTimeline() && !!offsetToViewTimelineRange(offset)
        : supportsScrollTimeline();
}
function useScroll({ container, target, ...options } = {}) {
    const values = useConstant(createScrollMotionValues);
    if (canAccelerateScroll(target, options.offset)) {
        values.scrollXProgress.accelerate = makeAccelerateConfig("x", options, container, target);
        values.scrollYProgress.accelerate = makeAccelerateConfig("y", options, container, target);
    }
    const scrollAnimation = useRef(null);
    const needsStart = useRef(false);
    const start = useCallback(() => {
        scrollAnimation.current = scroll((_progress, { x, y, }) => {
            values.scrollX.set(x.current);
            values.scrollXProgress.set(x.progress);
            values.scrollY.set(y.current);
            values.scrollYProgress.set(y.progress);
        }, {
            ...options,
            container: container?.current || undefined,
            target: target?.current || undefined,
        });
        return () => {
            scrollAnimation.current?.();
        };
    }, [container, target, JSON.stringify(options.offset)]);
    useIsomorphicLayoutEffect(() => {
        needsStart.current = false;
        if (isRefPending(container) || isRefPending(target)) {
            needsStart.current = true;
            return;
        }
        else {
            return start();
        }
    }, [start]);
    useEffect(() => {
        if (!needsStart.current)
            return;
        // Defer to a microtask so any sibling/parent effect that hydrates the
        // ref has a chance to run first.
        let cleanup;
        const tryStart = () => {
            const containerPending = isRefPending(container);
            const targetPending = isRefPending(target);
            invariant(!containerPending, "Container ref is defined but not hydrated", "use-scroll-ref");
            invariant(!targetPending, "Target ref is defined but not hydrated", "use-scroll-ref");
            if (!containerPending && !targetPending)
                cleanup = start();
        };
        microtask.read(tryStart);
        return () => {
            cancelMicrotask(tryStart);
            cleanup?.();
        };
    }, [start]);
    return values;
}

export { useScroll };
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