Sending a push notification from the RN App

SubjectListScene.js

_onPress = () => {
    const subjectsRef = firebase.database().ref('subjects');
    const notificationReqsRef = firebase.database().ref('notificationRequests');
    const subjectData = {
      author: 'TJ',
      title: this.state.subjectText,
    };
    const notificationReq = {
      from_username: 'TJ',
      message: `just posted new topic "${this.state.topicText}"`,
    };

    const newSubjectKey = subjectsRef.push().key;
    const newNotificationReqKey = notificationReqsRef.push().key;
  
    const updates = {};
    updates[`/topics/${newSubjectKey}`] = subjectData;
    updates[`/notificationRequests/${newNotificationReqKey}`] = notificationReq;
    firebase.database().ref().update(updates);

    this.setState({
      subjectText: '',
    });
  }