@helpscout/hsds-react/components/ChatScroller/ChatScroller.utils.js

React component library for Help Scout's Design System

"use strict";

exports.__esModule = true;
exports.allDefined = allDefined;
exports.shouldAutoScroll = shouldAutoScroll;
exports.getScrollProps = getScrollProps;

function allDefined(objs) {
  if (!objs) return false;
  var props = Array.isArray(objs) ? objs : Object.values(objs); // TODO: change when the other PR is merged for isNil
  // return props.filter(p => !isNil(p)).length === props.length

  return props.filter(function (p) {
    return p != null;
  }).length === props.length;
}
/**
 * Determines if the ChatScroller is within range of scrolling.
 *
 * @param   {Object} props
 * @returns {boolean}
 */


function shouldAutoScroll(props) {
  if (!allDefined(props)) return false;
  var distanceForAutoScroll = props.distanceForAutoScroll,
      scrollHeight = props.scrollHeight,
      scrollTop = props.scrollTop;
  return scrollTop + distanceForAutoScroll >= scrollHeight;
}
/**
 * Transforms, calculates, and defines props for scrolling.
 *
 * @param   {Object} props
 * @returns {Object}
 */


function getScrollProps(props) {
  if (!allDefined(props)) return {};
  var distanceForAutoScroll = props.distanceForAutoScroll,
      messageNode = props.messageNode,
      offsetThreshold = props.offsetThreshold,
      scrollableNode = props.scrollableNode;
  var scrollableHeight = scrollableNode.clientHeight;
  var scrollHeight = scrollableNode.scrollHeight;
  var scrollTop = scrollableNode.scrollTop + scrollableHeight + messageNode.clientHeight;
  var topOffset = scrollableHeight * offsetThreshold * -1;
  var position = messageNode.offsetTop + topOffset;
  return {
    distanceForAutoScroll: distanceForAutoScroll,
    position: position,
    scrollHeight: scrollHeight,
    scrollTop: scrollTop
  };
}