var gcm4node = require('gcm4node');

// only auth is REQUIRED
var config = {
    auth: 'YOUR_AUTH_KEY',
    dryRun: false,
    group_size: 1000,
    verbose: false
};
var gcm = gcm4node.gcm4node(config);

gcm.on('removed', function (removed) {
    console.log('removed devices: ' + removed.length);
});
gcm.on('updated', function (updated) {
    console.log('updated devices: ' + updated.length);
});
gcm.on('invalid', function (invalid) {
    console.log('invalid devices: ' + invalid.length);
});

// only the collapseKey option is REQUIRED
var options = {
    collapseKey: 'coll_key',
    delayWhileIdle: true,
    timeToLive: 0,
    data: {points: 5, user: 'pippo'}
};

// here you can put more than 1,000 clients
var clients = ['CLIENT_ID#1', 'CLIENT_ID#2', ..., 'CLIENT_ID#n'];

gcm.send(clients, options, function(err, removed, updated, invalid) {
    if (err)
        console.log('ops: ' + err);
    else
        console.log('removed: ' + removed.length +
            ', updated: ' + updated.length +
            ', invalid: ' + invalid.length);
});