Validating Signup Metadata

How to validate the optional metadata object passed from the client via accounts.signup().

When calling the accounts.signup() method from the client, you have the option of passing an additional metadata object alongside the email_address and password for the user being created. The metadata field is intended to contain additional information about the user (e.g., their name, their job title, etc).

Because this metadata object is passed directly from the client to your database by Joystick, it's important to validate its contents to ensure they match your expectations. To perform this validation, you can utilize the accounts.signup.metadata object passed to in your index.server.js file at the root of your project.

As an example, assume we had a call to accounts.signup() in the browser like this:

import { accounts } from '@joystick.js/ui';

  events: {
    'submit form': (event = {}, instance = {}) => {
        metadata: {
  render: () => {
    return `

Above, the metadata object is optional. While we do control what's passed to accounts.signup() in our code, because that function is accessible to any user on the client, a hypothetical attacker could pass arbitrary data to it via the metadata object.

To guard against this, on our server, we can define input validation for this field to prevent unexpected data from making it to the database:

import joystick from '@joystick.js/node';{
  accounts: {
    signup: {
      metadata: {
        company_name: {
          type: 'string',
          required: true,

In the example above, the object passed to accounts.signup.metadata is using the same input validation schema language that's used when you define getters and setters in your app's API.

When accounts.signup.metadata is set, Joystick will automatically validate that the metadata object passed to the server via accounts.signup() matches its expectations. If it doesn't, Joystick will throw an error and reject the signup request.