block10.js

// server/src/graphql/videoApi.js
...
const startSession = async (_, __, ___, ____) => {
  try {
    // initialize opentok
    initializeOpentok();

    // create the session
    const session = await createSession();

    // generate an id
    const uuid = uuidv4();

    // save the session
    videocalls.push({
      uuid,
      sessionId: session.sessionId,
    });

    // generate a token with moderator privileges
    const token = session.generateToken({
      role: 'moderator',
      data: `role=moderator`,
    });

    // return date honoring the format for SessionResponse type
    return {
      uuid,
      token,
      session: session.sessionId,
      apiKey,
    };
  } catch (e) {
    console.error('An error occurredocurred when creating opentok session', e);
  }
};
...