AngularFire2 Access Data After Retrieval

Question

I am trying to get data from my Firebase using AngularFire2. I want to check specific data, and after I get this data from Firebase, I can check it only in a certain area, and not after the operation with Firebase. Why is this happening?

Below is my code:

this.af.database.list('/users/1qfcMAQnglX9jsW5GdLpPko1HqE2', { preserveSnapshot: true}) .subscribe(snapshots=>{ snapshots.forEach(snapshot => { if(snapshot.key=="reg_boolean"){ console.log(snapshot.val()); this.bo=snapshot.val(); } this.currentUser.push({key:snapshot.key,value:snapshot.val()}); console.log(this.currentUser); //console.log(snapshot.key, snapshot.val()); if(this.bo==true){console.log("happy"); }; //i can access only in this scope }); }) if(this.bo==true){console.log("happy"); }; //why i can access this value??it undefined, this happen before the subscribe with angularfire2 

Answer 1

It is undefined because this.af.database.list it is asynchronous, so the code in subscribe will be executed when this.af.database.list will retrieve the data. So, when the code hit the line if(this.bo==true){console.log("happy"); }; if(this.bo==true){console.log("happy"); }; He has nothing, because the subscription has not ended at all.

Subscribe to it as an old promise, but now it works with rxjs. I recommend that you study it, because angular and ionic pay a lot of attention to this.

Try looking at https://www.learnrxjs.io/