adobe.target.sendNotifications(options)

function createTokens(options) {
  return options.map(e => e.eventToken);
}

function createNotification(mbox, type, tokens) {
  const id = 11111; // here we should use a random ID like UUID
  const timestamp = Date.now();
  const { name, state, parameters, profileParameters, order, product } = mbox;
  const result = {
    id,
    type,
    timestamp,
    parameters,
    profileParameters,
    order,
    product
  };

  result.mbox = { name, state };
  result.tokens = tokens;

  return result;
}

adobe.target.getOffers({
  request: {
    prefetch: {
      mboxes: [
        {
          index: 0,
          name: "a1-serverside-ab"
        }
      ]
    }
  }
})
.then(response => {
  const mboxes = response.prefetch.mboxes;
  const notifications = mboxes.map(mbox => {
    const type = "display";
    const tokens = createTokens(mbox.options);

    return createNotification(mbox, type, tokens);
  });

  adobe.target.sendNotifications({
    request: { notifications }
  });
})