@mui/material/useScrollTrigger/useScrollTrigger.js

Quickly build beautiful React apps. MUI is a simple and customizable component library to build faster, beautiful, and more accessible React applications. Follow your own design system, or start with Material Design.

import _extends from "@babel/runtime/helpers/esm/extends";
import _objectWithoutPropertiesLoose from "@babel/runtime/helpers/esm/objectWithoutPropertiesLoose";
const _excluded = ["getTrigger", "target"];
import * as React from 'react';

function defaultTrigger(store, options) {
  const {
    disableHysteresis = false,
    threshold = 100,
    target
  } = options;
  const previous = store.current;

  if (target) {
    // Get vertical scroll
    store.current = target.pageYOffset !== undefined ? target.pageYOffset : target.scrollTop;
  }

  if (!disableHysteresis && previous !== undefined) {
    if (store.current < previous) {
      return false;
    }
  }

  return store.current > threshold;
}

const defaultTarget = typeof window !== 'undefined' ? window : null;
export default function useScrollTrigger(options = {}) {
  const {
    getTrigger = defaultTrigger,
    target = defaultTarget
  } = options,
        other = _objectWithoutPropertiesLoose(options, _excluded);

  const store = React.useRef();
  const [trigger, setTrigger] = React.useState(() => getTrigger(store, other));
  React.useEffect(() => {
    const handleScroll = () => {
      setTrigger(getTrigger(store, _extends({
        target
      }, other)));
    };

    handleScroll(); // Re-evaluate trigger when dependencies change

    target.addEventListener('scroll', handleScroll);
    return () => {
      target.removeEventListener('scroll', handleScroll);
    }; // See Option 3. https://github.com/facebook/react/issues/14476#issuecomment-471199055
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [target, getTrigger, JSON.stringify(other)]);
  return trigger;
}