Handle Errors

Errors may happen in different layers. You may get notified in different ways dependent on where the error happens.

Missing Required OAuth Parameters

If you forget to set the required OAuth parameters, such as the client_id or scope, you'll see an error message like below in your browser's JavaScript Console.

Fix OAuth Configuration Errors

Changes in the Google APIs console may be required to resolve some errors.

• Creates a client ID if not yet.
• For popup UX, add all domains that may trigger the current flow to Authorized JavaScript origins.
• For redirect UX, add all URLs that may receive authorization responses to Authorized redirect URIs.
• Properly configure your OAuth Consent screen.
  • Submit your app for verification if needed.
• You might need to take additional steps to comply with Google's OAuth 2.0 Policies.

Invalid OAuth Parameter Values

If you set the invalid values to OAuth parameters, such as the invalid client id , scope identifiers, or response type values, you'll see the OAuth error page.

OAuth Error Responses

OAuth may return an error response, in which case your callback function will be triggered with the error response as the parameter. The following is an example OAuth error response.

  {
    "error":"access_denied"
  }

Some examples are listed as below.

1. The user denies the OAuth request.
2. For an OAuth request with prompt=none parameter, the user is not already authenticated and has not pre-configured consent for the requested scopes.

The example below shows how to handle the success and error OAuth responses.

function myCallback(response) {
  if (response.error) {
    // Handle error response
    ... ...
  } else if (response.code) {
    // Handle success code response
    ... ...
  }
}

Non-OAuth Errors

OAuth doesn't define the behaviors when:

1. the popup window fails to open.
2. the popup window is closed before an OAuth response is returned.

This library captures these errors, and triggers the error_callback if set. Be sure to check the error type like below. Otherwise, your code logic may be affected when this library support new error types later.

function myErrorCallback(err) {
  if (err.type == 'popup_failed_to_open') {
    // The popup window is failed to open
    ... ...
  } else if (err.type == 'popup_closed') {
    // The popup window is closed before an OAuth response is returned
    ... ...
  }
}

const client = google.accounts.oauth2.initCodeClient({
  client_id: 'YOUR_GOOGLE_CLIENT_ID',
  scope: 'https://www.googleapis.com/auth/calendar.readonly',
  ux_mode: 'popup',
  callback: myCallback,
  error_callback: myErrorCallback
});