@react-aria/utils/src/useDescription.ts

/*
 * Copyright 2020 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

import {AriaLabelingProps} from '@react-types/shared';
import {useLayoutEffect} from './useLayoutEffect';
import {useState} from 'react';

let descriptionId = 0;
const descriptionNodes = new Map<string, {refCount: number, element: HTMLElement}>();

export function useDescription(description: string): AriaLabelingProps {
  let [id, setId] = useState(null);

  useLayoutEffect(() => {
    if (!description) {
      return;
    }

    let desc = descriptionNodes.get(description);
    if (!desc) {
      let id = `react-aria-description-${descriptionId++}`;
      setId(id);

      let node = document.createElement('div');
      node.id = id;
      node.style.display = 'none';
      node.textContent = description;
      document.body.appendChild(node);
      desc = {refCount: 0, element: node};
      descriptionNodes.set(description, desc);
    } else {
      setId(desc.element.id);
    }

    desc.refCount++;
    return () => {
      if (--desc.refCount === 0) {
        desc.element.remove();
        descriptionNodes.delete(description);
      }
    };
  }, [description]);

  return {
    'aria-describedby': description ? id : undefined
  };
}