Just last week, at Google I/O, Google announced Google Cloud Messaging for iOS.
Relaying on the official Google Cloud Messaging Pod, Christian Sullivan is now offering its full capability to all React Native developers out there.

react-native-gcm on GitHub

Usage

// Register for Push Notifications
gcm.register()

// Subscribe to topic
gcm.topicSubscribe('/topics/test', (err, res) => {});

// Unsubscribe from topic
gcm.topicUnsubscribe('/topics/test', (err, res) => {});

// Send upstream message
gcm.sendMessage({
    id: '' // unique message id
    to: '', // recip id
    ttl: 500 // optional time to live
    message: {}, // msg data
});

GCM has all "EventEmitter" methods

// Connected to GCM socket
gcm.on("connection", (res) => {});

// Disconnected from GCM socket
gcm.on("disconnect", (res) => {});

// Client registered with gcm
gcm.on("registeredClient", (res) => {});

// Application entered background
gcm.on("enteredBackground", (res) => {});

// Application became active again
gcm.on("becameActive", (res) => {});

// Received message from GCM
gcm.on("message", (res) => {});