How to wait firebase to loaded data before render page











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I have a function that getting data from firebase realtime database.
But It's seem like it's took some time so my parameter "doPosttest1" is always false and after a second, if found data "doPosttest1" will change but it too late.



How can I do async or wait until data loaded, then render the page?



Thank you.



PS. I'm using Ionic V.3



// Check posttest 1

let doPosttest1 = false;

var refPosttestSubject1 = this.db.database.ref("/testSubmit/Onboard-Safety-and-Security/posttest");

refPosttestSubject1.orderByChild("email").equalTo(this.auth.currentUser.email).on("child_added", function (snapshot) {

  doPosttest1 = true;

  console.log(snapshot.key + " was " + snapshot.val().name + " meters tall");

});



this.isDoPosttest1 = doPosttest1;





typescript ionic-framework firebase-realtime-database ionic3







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  • did you try to also add the this.isDoPosttest1 = doPosttest1; line, between doPosttest1 = true; and the console.log... ?
    – Octavio Garbarino
    Nov 21 at 15:07










  • yes, but it's doesn't know "this.isDoPostTest1". So i have to to like this.
    – Ittiwut Wongsawat
    Nov 22 at 2:16















up vote
1
down vote

favorite












I have a function that getting data from firebase realtime database.
But It's seem like it's took some time so my parameter "doPosttest1" is always false and after a second, if found data "doPosttest1" will change but it too late.



How can I do async or wait until data loaded, then render the page?



Thank you.



PS. I'm using Ionic V.3



// Check posttest 1

let doPosttest1 = false;

var refPosttestSubject1 = this.db.database.ref("/testSubmit/Onboard-Safety-and-Security/posttest");

refPosttestSubject1.orderByChild("email").equalTo(this.auth.currentUser.email).on("child_added", function (snapshot) {

  doPosttest1 = true;

  console.log(snapshot.key + " was " + snapshot.val().name + " meters tall");

});



this.isDoPosttest1 = doPosttest1;





typescript ionic-framework firebase-realtime-database ionic3







share|improve this question






















  • did you try to also add the this.isDoPosttest1 = doPosttest1; line, between doPosttest1 = true; and the console.log... ?
    – Octavio Garbarino
    Nov 21 at 15:07










  • yes, but it's doesn't know "this.isDoPostTest1". So i have to to like this.
    – Ittiwut Wongsawat
    Nov 22 at 2:16













up vote
1
down vote

favorite









up vote
1
down vote

favorite











I have a function that getting data from firebase realtime database.
But It's seem like it's took some time so my parameter "doPosttest1" is always false and after a second, if found data "doPosttest1" will change but it too late.



How can I do async or wait until data loaded, then render the page?



Thank you.



PS. I'm using Ionic V.3



// Check posttest 1

let doPosttest1 = false;

var refPosttestSubject1 = this.db.database.ref("/testSubmit/Onboard-Safety-and-Security/posttest");

refPosttestSubject1.orderByChild("email").equalTo(this.auth.currentUser.email).on("child_added", function (snapshot) {

  doPosttest1 = true;

  console.log(snapshot.key + " was " + snapshot.val().name + " meters tall");

});



this.isDoPosttest1 = doPosttest1;





typescript ionic-framework firebase-realtime-database ionic3







share|improve this question













I have a function that getting data from firebase realtime database.
But It's seem like it's took some time so my parameter "doPosttest1" is always false and after a second, if found data "doPosttest1" will change but it too late.



How can I do async or wait until data loaded, then render the page?



Thank you.



PS. I'm using Ionic V.3



// Check posttest 1

let doPosttest1 = false;

var refPosttestSubject1 = this.db.database.ref("/testSubmit/Onboard-Safety-and-Security/posttest");

refPosttestSubject1.orderByChild("email").equalTo(this.auth.currentUser.email).on("child_added", function (snapshot) {

  doPosttest1 = true;

  console.log(snapshot.key + " was " + snapshot.val().name + " meters tall");

});



this.isDoPosttest1 = doPosttest1;





typescript ionic-framework firebase-realtime-database ionic3




typescript ionic-framework firebase-realtime-database ionic3






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 21 at 13:37









Ittiwut Wongsawat

63




63












  • did you try to also add the this.isDoPosttest1 = doPosttest1; line, between doPosttest1 = true; and the console.log... ?
    – Octavio Garbarino
    Nov 21 at 15:07










  • yes, but it's doesn't know "this.isDoPostTest1". So i have to to like this.
    – Ittiwut Wongsawat
    Nov 22 at 2:16


















  • did you try to also add the this.isDoPosttest1 = doPosttest1; line, between doPosttest1 = true; and the console.log... ?
    – Octavio Garbarino
    Nov 21 at 15:07










  • yes, but it's doesn't know "this.isDoPostTest1". So i have to to like this.
    – Ittiwut Wongsawat
    Nov 22 at 2:16
















did you try to also add the this.isDoPosttest1 = doPosttest1; line, between doPosttest1 = true; and the console.log... ?
– Octavio Garbarino
Nov 21 at 15:07




did you try to also add the this.isDoPosttest1 = doPosttest1; line, between doPosttest1 = true; and the console.log... ?
– Octavio Garbarino
Nov 21 at 15:07












yes, but it's doesn't know "this.isDoPostTest1". So i have to to like this.
– Ittiwut Wongsawat
Nov 22 at 2:16




yes, but it's doesn't know "this.isDoPostTest1". So i have to to like this.
– Ittiwut Wongsawat
Nov 22 at 2:16

















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