appendToPlugin.js

/**
 * @license
 *
 * Copyright IBM Corp. 2019
 *
 * This source code is licensed under the Apache-2.0 license found in the
 * LICENSE file in the root directory of this source tree.
 */

/**
 * @param {object} config Plugin configuration.
 * @returns {Plugin} A Flatpickr plugin to put adjust the position of calendar dropdown.
 */
export default (config) => (fp) => {
  /**
   * Adjusts the floating menu position after Flatpicker sets it.
   */
  const handlePreCalendarPosition = () => {
    Promise.resolve().then(() => {
      const {
        calendarContainer,
        config: fpConfig,
        _positionElement: positionElement,
      } = fp;
      const { appendTo } = fpConfig;
      const { left: containerLeft, top: containerTop } =
        appendTo.getBoundingClientRect();
      const { left: refLeft, bottom: refBottom } =
        positionElement.getBoundingClientRect();
      if (
        (appendTo !== appendTo.ownerDocument.body ||
          containerLeft !== 0 ||
          containerTop !== 0) &&
        appendTo.ownerDocument.defaultView
          .getComputedStyle(appendTo)
          .getPropertyValue('position') === 'static'
      ) {
        throw new Error(
          'Floating menu container must not have `position:static`.'
        );
      }
      // `2` for negative margin on calendar dropdown
      calendarContainer.style.top = `${refBottom - containerTop + 2}px`;
      calendarContainer.style.left = `${refLeft - containerLeft}px`;
    });
  };

  /**
   * Registers this Flatpickr plugin.
   */
  const register = () => {
    fp.loadedPlugins.push('carbonFlatpickrAppendToPlugin');
  };

  return {
    appendTo: config.appendTo,
    onReady: register,
    onPreCalendarPosition: handlePreCalendarPosition,
  };
};