react-selectable-box/es/hooks/useScroll.js

A React component used hooks that allows you to select elements in the drag area using the mouse

import { useEffect, useRef } from 'react';
import { getClientXY } from "../utils";
var DEFAULT_SCROLL_SPEED = 4;
var EDGE_OFFSET = 1;
export default function useScroll() {
  var scrollSpeed = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : DEFAULT_SCROLL_SPEED;
  var scrollContainer = arguments.length > 1 ? arguments[1] : undefined;
  var topRaf = useRef(null);
  var bottomRaf = useRef(null);
  var leftRaf = useRef(null);
  var rightRaf = useRef(null);
  var cancelRaf = function cancelRaf(raf) {
    if (raf.current) {
      cancelAnimationFrame(raf.current);
      raf.current = null;
    }
  };
  var cancelScroll = function cancelScroll() {
    cancelRaf(topRaf);
    cancelRaf(bottomRaf);
    cancelRaf(leftRaf);
    cancelRaf(rightRaf);
  };
  useEffect(function () {
    return cancelScroll;
  }, []);
  var getScrollContainer = function getScrollContainer(axis) {
    function getContainer() {
      if (scrollContainer) {
        var _scrollContainer$inne, _scrollContainer$oute;
        if (typeof scrollContainer === 'function') {
          return scrollContainer();
        }
        if (((_scrollContainer$inne = scrollContainer.inner) === null || _scrollContainer$inne === void 0 ? void 0 : _scrollContainer$inne.axis) === axis) {
          return scrollContainer.inner.getContainer();
        }
        if (((_scrollContainer$oute = scrollContainer.outer) === null || _scrollContainer$oute === void 0 ? void 0 : _scrollContainer$oute.axis) === axis) {
          return scrollContainer.outer.getContainer();
        }
      }
      return document.body;
    }
    var container = getContainer();
    return container === document.body ? document.documentElement : container;
  };
  var smoothScroll = function smoothScroll(e) {
    var _getClientXY = getClientXY(e),
      clientX = _getClientXY.clientX,
      clientY = _getClientXY.clientY;
    var xScrollContainer = getScrollContainer('x');
    var yScrollContainer = getScrollContainer('y');
    if (yScrollContainer) {
      // top
      if (clientY - EDGE_OFFSET <= 0 || clientY <= yScrollContainer.getBoundingClientRect().top) {
        if (!topRaf.current) {
          var callback = function callback() {
            if (yScrollContainer.scrollTop > 0) {
              topRaf.current = requestAnimationFrame(function () {
                yScrollContainer.scrollTop -= scrollSpeed;
                callback();
              });
            }
          };
          callback();
        }
      } else {
        cancelRaf(topRaf);
      }

      // bottom
      if (clientY + EDGE_OFFSET >= window.innerHeight || clientY >= yScrollContainer.getBoundingClientRect().bottom) {
        if (!bottomRaf.current) {
          var _callback = function _callback() {
            if (yScrollContainer.scrollTop < yScrollContainer.scrollHeight - yScrollContainer.clientHeight) {
              bottomRaf.current = requestAnimationFrame(function () {
                yScrollContainer.scrollTop += scrollSpeed;
                _callback();
              });
            }
          };
          _callback();
        }
      } else {
        cancelRaf(bottomRaf);
      }
    }
    if (xScrollContainer) {
      // left
      if (clientX - EDGE_OFFSET <= 0 || clientX <= xScrollContainer.getBoundingClientRect().left) {
        if (!leftRaf.current) {
          var _callback2 = function _callback2() {
            if (xScrollContainer.scrollLeft > 0) {
              leftRaf.current = requestAnimationFrame(function () {
                xScrollContainer.scrollLeft -= scrollSpeed;
                _callback2();
              });
            }
          };
          _callback2();
        }
      } else {
        cancelRaf(leftRaf);
      }

      // right
      if (clientX + EDGE_OFFSET >= window.innerWidth || clientX >= xScrollContainer.getBoundingClientRect().right) {
        if (!rightRaf.current) {
          var _callback3 = function _callback3() {
            if (xScrollContainer.scrollLeft < xScrollContainer.scrollWidth - xScrollContainer.clientWidth) {
              rightRaf.current = requestAnimationFrame(function () {
                xScrollContainer.scrollLeft += scrollSpeed;
                _callback3();
              });
            }
          };
          _callback3();
        }
      } else {
        cancelRaf(rightRaf);
      }
    }
  };
  return {
    cancelScroll: cancelScroll,
    smoothScroll: smoothScroll
  };
}