Fixin async set state

setstate.js

//----------------First---------------------------

componentDidMount() {
    const events = [];
    firebase
      .collection("events")
      .get()
      .then(function(querySnapshot) {
        querySnapshot.forEach(function(doc) {
          events.push(doc.data());
        });
        this.setState({
          eventContainer: events
        });
      })
  }

//==============Second=======================
  
componentDidMount() {
    const events = [];
    firebase
      .collection("events")
      .get()
      .then(function(querySnapshot) {
        querySnapshot.forEach(function(doc) {
          events.push(doc.data());
        });
      })
      .then(function() {
        this.setState({
          eventContainer: events
        });
      });
  }