vktr

function (user, context, callback) {
  user.app_metadata = user.app_metadata || {};

  if ('stripe_customer_id' in user.app_metadata) {
    context.idToken['https://example.com/stripe_customer_id'] = user.app_metadata.stripe_customer_id;
    return callback(null, user, context);
  }

  var stripe = require('stripe')('sk_....');
  var customer = {