Basic Facebook login and data retrieval flow

basic-facebook-login-flow.js

// Check and verify user status or prompt for authorization
function checkUserStatus(response) {
  var permissions = {
    scope: '' // email
  };

  if ( isConnectedUser(response) ) 
    return FB.api('/me', gotUserInfo);
  return FB.login(checkUserStatus, permissions);
}

// Check if user is authorized and connected
function isConnectedUser(response) {
  return (response && response.status && response.status === 'connected') ? true : false;
}

// Get and process user info
function gotUserInfo(info) {
  console.log(info);
}


// Call it as following
FB.getLoginStatus(checkUserStatus);