To check authentication status:

platform.isAuthorized()

    .then(function(){ ... })

    .catch(function(e){ ... });

The isAuthorized method will automatically perform a refresh of the access token, if needed. This method may be used in the login page of your application for automatic login.

There is also a synchronous method for checking the authentication status that does not automatically perform a refresh of the access token.

if (platform.isTokenValid()) {...}

Access token refresh normally happens automatically for common use cases. On rare occasions, you may perform a refresh of the access token manually by calling the refresh method, as follows:

platform.refresh().then(...)