@elastic/eui/es/components/code/code_block_overflow.js

Elastic UI Component Library

function _typeof(obj) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (obj) { return typeof obj; } : function (obj) { return obj && "function" == typeof Symbol && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }, _typeof(obj); }
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function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return _typeof(key) === "symbol" ? key : String(key); }
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function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }
function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }
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function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */

import { useEffect, useState, useMemo } from 'react';
import { useMutationObserver } from '../observer/mutation_observer';
import { useResizeObserver } from '../observer/resize_observer';

/**
 * Overflow logic - returns overflow-related state/logic/utils
 *
 * Detects whether the code block overflows and returns a tabIndex of 0 if so,
 * which allows keyboard users to use the up/down arrow keys to scroll through
 * the container.
 */
export var useOverflow = function useOverflow(_ref) {
  var overflowHeight = _ref.overflowHeight;
  var _useState = useState(null),
    _useState2 = _slicedToArray(_useState, 2),
    wrapperRef = _useState2[0],
    setWrapperRef = _useState2[1];
  var _useState3 = useState(-1),
    _useState4 = _slicedToArray(_useState3, 2),
    tabIndex = _useState4[0],
    setTabIndex = _useState4[1];
  var _useResizeObserver = useResizeObserver(wrapperRef),
    width = _useResizeObserver.width,
    height = _useResizeObserver.height;
  var doesOverflow = function doesOverflow() {
    if (!wrapperRef) return;
    var clientWidth = wrapperRef.clientWidth,
      clientHeight = wrapperRef.clientHeight,
      scrollWidth = wrapperRef.scrollWidth,
      scrollHeight = wrapperRef.scrollHeight;
    var doesOverflow = scrollHeight > clientHeight || scrollWidth > clientWidth;
    setTabIndex(doesOverflow ? 0 : -1);
  };
  useMutationObserver(wrapperRef, doesOverflow, {
    subtree: true,
    childList: true
  });
  useEffect(doesOverflow, [width, height, wrapperRef]);
  var overflowHeightStyles = useMemo(function () {
    if (overflowHeight) {
      var property = typeof overflowHeight === 'string' ? 'blockSize' : 'maxBlockSize';
      return _defineProperty({}, property, overflowHeight);
    }
    return {};
  }, [overflowHeight]);
  return {
    setWrapperRef: setWrapperRef,
    tabIndex: tabIndex,
    overflowHeightStyles: overflowHeightStyles
  };
};