YouTube service setup for use with OAuth2 for Apps Script https://github.com/googlesamples/apps-script-oauth2

YouTubeOAuth2Service.gs

/* Setup

1. In the Script Editor select Resources > Cloud platform project... and click the link to the currently associated project

2. In the Google Cloud Platform window click "Go to APIs overview"

3. In APIs & services click "Enable APIs and Services"

4. In the Library search/click on YouTube Data API and click 'Enable'

5. Still in the APIs & services screen click on Credentials from the side menu

6. Click the 'Create credentials', select 'OAuth Client ID' then 'Web application'

7. Enter a name as required and in the 'Authorised JavaScript origins' enter https://script.google.com 

8. In this script project Run > Run function > logRedirectUri. From the View > Logs copy the url into the 'Authorised redirect URIs' field API console, click 'Create'

9. In this script project open File > Project properties and in the Script properties tab and new rows for client_id and client_secret copying the values from the API console 

10. In this script project Run> Run function > setup and and then from the View > Logs copy the url in a new browser tab. Select the YouTube account you would like to use with this script project

*/

/**
 * Authorizes and makes a request to the YouTube API.
 */
function setup() {
  var service = getYouTubeService();
  YouTube.setTokenService(function(){ return service.getAccessToken(); });
  if (service.hasAccess()) {
    var result = YouTube.channelsList("snippet", {mine:true});
    Logger.log(JSON.stringify(result, null, 2));
    throw "Open View > Logs to see result";
  } else {
    var authorizationUrl = service.getAuthorizationUrl();
    Logger.log('Open the following URL and re-run the script: %s',
        authorizationUrl);
    throw "Open View > Logs to get authentication url";
  }
}

/**
 * Configures the service.
 */
function getYouTubeService() {
  return OAuth2.createService('YouTube')
      // Set the endpoint URLs.
      .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/auth')
      .setTokenUrl('https://accounts.google.com/o/oauth2/token')

      // Set the client ID and secret.
      .setClientId(getStaticScriptProperty_('client_id'))
      .setClientSecret(getStaticScriptProperty_('client_secret'))

      // Set the name of the callback function that should be invoked to complete
      // the OAuth flow.
      .setCallbackFunction('authCallback')

      // Set the property store where authorized tokens should be persisted
      // you might want to switch to Script Properties if sharing access
      .setPropertyStore(PropertiesService.getUserProperties())

      // Set the scope and additional Google-specific parameters.
      .setScope(["https://www.googleapis.com/auth/youtube",
      "https://www.googleapis.com/auth/youtube.force-ssl",
      "https://www.googleapis.com/auth/youtube.readonly",
      "https://www.googleapis.com/auth/youtubepartner",
      "https://www.googleapis.com/auth/youtubepartner-channel-audit"])
      .setParam('access_type', 'offline');
}

/**
 * Handles the OAuth callback.
 */
function authCallback(request) {
  var service = getYouTubeService();
  var authorized = service.handleCallback(request);
  if (authorized) {
    return HtmlService.createHtmlOutput('Success!');
  } else {
    return HtmlService.createHtmlOutput('Denied');
  }
}

/**
 * Logs the redirect URI to register in the Google Developers Console.
 */
function logRedirectUri() {
  var service = getYouTubeService();
  Logger.log(service.getRedirectUri());
  throw "Open View > Logs to get redirect url";
}

/**
 * Reset the authorization state, so that it can be re-tested.
 */
function reset() {
  var service = getYouTubeService();
  service.reset();
}

/**
 * Gets a static script property, using long term caching.
 * @param {string} key The property key.
 * @returns {string} The property value.
 */
function getStaticScriptProperty_(key) {
  var value = CacheService.getScriptCache().get(key);
  if (!value) {
    value = PropertiesService.getScriptProperties().getProperty(key);
    CacheService.getScriptCache().put(key, value, 21600);
  }
  return value;
}

TypeError: Function setTokenService not found on object AdvancedServiceIdentifier {name = youtube, version = v3}

line 30: YouTube.setTokenService(function(){ return service.getAccessToken(); });

ReferenceError: YouTube is not defined