This is the code for a YouTube playlist script for Scriptable.app

YouTube Playlist Script

let playlistID, startDay, API_KEY
if (args.widgetParameter) {    
  [playlistID, startDay, API_KEY] = args.widgetParameter.split(",")
}
const url = `https://youtube.googleapis.com/youtube/v3/playlistItems?part=snippet%2CcontentDetails&maxResults=30&playlistId=${playlistID}&key=${API_KEY}`

const getCurrentDay = () => {
  const today = new Date()  
  const startDate = new Date(startDay)  
  const differenceInTime = today.getTime() - startDate.getTime()  
  return parseInt(differenceInTime / (1000 * 3600 * 24), 10)
}

const getTodaysVideo = async () => {
  if (!playlistID || !startDay || !API_KEY) {
    return new Promise((resolve) => resolve(["Bitte das Widget mit Playlist-ID, Startdatum und API_KEY konfigurieren", null, null]))
  }
  const request = new Request(url)  
  request.headers = {"Accept": "application/json"}  
  const response = await request.loadJSON()
  const allVideos = response.items

  const todaysVideo = allVideos[getCurrentDay()]
  let title, image, videoId
  if (todaysVideo) {
    videoId = todaysVideo.snippet.resourceId.videoId
    const thumbnailUrl = todaysVideo.snippet.thumbnails.high.url
    
    const imageRequest = new Request(thumbnailUrl)
    const thumbnailData = await imageRequest.load()
    image = Image.fromData(thumbnailData)
  } else {
    title = "Playlist ohne heutiges Video.\nIst die Playlist beendet?\n😱"
  }
  return [title, image, videoId]
}

async function createWidget(title, image, videoId) {
  const widget = new ListWidget()

  widget.backgroundColor = new Color("#eeeee4")
  
  if (image) {
    const widgetImage = widget.addImage(image)
    widgetImage.applyFillingContentMode()

    let gradient = new LinearGradient()
    gradient.locations = [0, 1]
    gradient.colors = [
      new Color("#eeeee4"),
      new Color("#eab676")
    ]
    widget.backgroundGradient = gradient
    // Add spacer above content to center it vertically.
    widget.addSpacer()
  }

  if (videoId) {
    widget.url = `https://m.youtube.com/watch?v=${videoId}`
  }
  
  if (title) {
    const widgetText = widget.addText(title)
    widgetText.textColor = new Color("#000000")
  }
  
  return widget
}

const [title, image, videoId] = await getTodaysVideo()
let widget = await createWidget(title, image, videoId)
Script.setWidget(widget)

Script.complete()