getDimensions.js

const getNewDimensions = (playerInstance: jwplayer.JWPlayer | null): Dimension => {
  const container = playerInstance.getContainer();

  const parentContainerWidth = container && container.parentElement.offsetWidth;

  let parentContainerHeight = container && container.parentElement.offsetHeight;

  // get the window size, overcoming simulator bug of misplacing the actual screen size property value
  const windowWidth = Math.min(window.innerWidth, window.outerWidth);
  console.log(windowWidth)
  // only tweak height for mobile phone widths
  if (windowWidth <= PHONE_SIZE) {
    const playlistItem = playerInstance.getPlaylistItem();

    // calculate the actual video media aspect ratio
    const currentVideoWidth = playlistItem.allSources[1].width;
    const currentVideoHeight = playlistItem.allSources[1].height;
    const currentVideoRatio = currentVideoWidth / currentVideoHeight;

    // calculate the new desired player height
    parentContainerHeight = parentContainerWidth / currentVideoRatio;
  }

  return {
    height: parentContainerHeight,
    width: parentContainerWidth,
  };
};

refactored.js

import { PHONE_SIZE } from '../constants';

type Dimension = {
  width: number;
  height: number;
};

const calculateRatio = (width: number, height: number): number => width / height;

const calculateHeight = (containerWidth: number, videoWidth: number, videoHeight: number) =>
  containerWidth / calculateRatio(videoWidth, videoHeight);

const getNewDimensions = (playerInstance: jwplayer.JWPlayer | null): Dimension => {
  const container = playerInstance.getContainer();

  const width = container && container.parentElement.offsetWidth;
  const height = container && container.parentElement.offsetHeight;

  // get the window size, overcoming simulator bug of misplacing the actual screen size property value
  const windowWidth = Math.min(window.innerWidth, window.outerWidth);
  if (windowWidth > PHONE_SIZE) {
    return { height, width };
  }

  const [, video] = playerInstance.getPlaylistItem().allSources;
  return {
    height: calculateHeight(width, video.width, video.height),
    width,
  };
};

export default getNewDimensions;