Google Sheets Custom Functions: Get YouTube Channel ID or Channel Title from a YT Video ID

appsScript.js

// This code: https://gist.github.com/cliffordp/c953c2e4020935727948afe29bd0f192

// Could use YouTube Service instead: https://developers.google.com/apps-script/advanced/youtube

// https://developers.google.com/youtube/v3/docs
const YouTubeApiKey = '...';

// `=getChannelIdFromVideoId( A1 )`
// Could link if you wish: `="https://www.youtube.com/channel/"&B1`
function getChannelIdFromVideoId( videoId ) {
  const data = getDataFromVideoId( videoId );

  if( isString( data ) ) {
    return data;
  }

  return data.items[0].snippet.channelId;
}

// `=getChannelTitleFromVideoId( A1 )`
function getChannelTitleFromVideoId( videoId ) {
  const data = getDataFromVideoId( videoId );

  if( isString( data ) ) {
    return data;
  }
  
  return data.items[0].snippet?.channelTitle;
}

// https://developers.google.com/apps-script/guides/services/external
function getDataFromVideoId( videoId ) {
  const apiUrl = getApiCallUrl( videoId );

  // https://developers.google.com/apps-script/reference/url-fetch/url-fetch-app
  const response = UrlFetchApp.fetch( apiUrl, { 'muteHttpExceptions': true } );
  const json = response.getContentText();
  const data = JSON.parse(json);

  const apiErrorMessage = getApiErrorMessage( data );
  if( apiErrorMessage !== '' ) {
    return 'ERROR: ' + apiErrorMessage;
  }

  if( data.items.length === 0 ) {
    console.log( 'Video not found.' );

    return '';
  }

  return data;
}

function getApiCallUrl( videoId ) {
  return 'https://www.googleapis.com/youtube/v3/videos?part=id%2C+snippet&id=' + videoId + '&key=' + YouTubeApiKey;
}

// https://developers.google.com/youtube/v3/getting-started#quota
function getApiErrorMessage( data ) {
  console.log( data);
  if( data.error?.errors.length > 0 ) {
    return data.error.errors[0].reason; // e.g. "quotaExceeded"
  }

  return '';
}

function isString(s) {
    return typeof(s) === 'string' || s instanceof String;
}