Computed property whose value results from an API call










1















An API call (Firebase) determines the return value of my computed property and hence whether I display certain elements in my template.



Yet, my computed property is actually not reactive: its value in my template doesn't change upon the API call. Why not?



JS:



myComputedProperty: function() 
firebase.auth().onAuthStateChanged(function(user)
if (user)
return true;

else
return false;

);



Template:



<span v-if="userConnected">
User connected
</span>









share|improve this question




























    1















    An API call (Firebase) determines the return value of my computed property and hence whether I display certain elements in my template.



    Yet, my computed property is actually not reactive: its value in my template doesn't change upon the API call. Why not?



    JS:



    myComputedProperty: function() 
    firebase.auth().onAuthStateChanged(function(user)
    if (user)
    return true;

    else
    return false;

    );



    Template:



    <span v-if="userConnected">
    User connected
    </span>









    share|improve this question


























      1












      1








      1








      An API call (Firebase) determines the return value of my computed property and hence whether I display certain elements in my template.



      Yet, my computed property is actually not reactive: its value in my template doesn't change upon the API call. Why not?



      JS:



      myComputedProperty: function() 
      firebase.auth().onAuthStateChanged(function(user)
      if (user)
      return true;

      else
      return false;

      );



      Template:



      <span v-if="userConnected">
      User connected
      </span>









      share|improve this question
















      An API call (Firebase) determines the return value of my computed property and hence whether I display certain elements in my template.



      Yet, my computed property is actually not reactive: its value in my template doesn't change upon the API call. Why not?



      JS:



      myComputedProperty: function() 
      firebase.auth().onAuthStateChanged(function(user)
      if (user)
      return true;

      else
      return false;

      );



      Template:



      <span v-if="userConnected">
      User connected
      </span>






      javascript vue.js computed-properties






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 13 '18 at 18:33









      Bhojendra Rauniyar

      51k2079125




      51k2079125










      asked Nov 13 '18 at 18:13









      drake035drake035

      489124199




      489124199






















          1 Answer
          1






          active

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          2














          Your return value isn't the return value for your computed property. It's the return value of the callback function.



          You should be using data() and created() or mounted() to check this instead:



          data () 
          return
          isAuthenticated: false
          ;

          ,
          created ()
          firebase.auth().onAuthStateChanged((user) =>
          this.isAuthenticated = !!user
          );






          share|improve this answer






















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            1 Answer
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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2














            Your return value isn't the return value for your computed property. It's the return value of the callback function.



            You should be using data() and created() or mounted() to check this instead:



            data () 
            return
            isAuthenticated: false
            ;

            ,
            created ()
            firebase.auth().onAuthStateChanged((user) =>
            this.isAuthenticated = !!user
            );






            share|improve this answer



























              2














              Your return value isn't the return value for your computed property. It's the return value of the callback function.



              You should be using data() and created() or mounted() to check this instead:



              data () 
              return
              isAuthenticated: false
              ;

              ,
              created ()
              firebase.auth().onAuthStateChanged((user) =>
              this.isAuthenticated = !!user
              );






              share|improve this answer

























                2












                2








                2







                Your return value isn't the return value for your computed property. It's the return value of the callback function.



                You should be using data() and created() or mounted() to check this instead:



                data () 
                return
                isAuthenticated: false
                ;

                ,
                created ()
                firebase.auth().onAuthStateChanged((user) =>
                this.isAuthenticated = !!user
                );






                share|improve this answer













                Your return value isn't the return value for your computed property. It's the return value of the callback function.



                You should be using data() and created() or mounted() to check this instead:



                data () 
                return
                isAuthenticated: false
                ;

                ,
                created ()
                firebase.auth().onAuthStateChanged((user) =>
                this.isAuthenticated = !!user
                );







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 13 '18 at 18:17









                BrianBrian

                3,2111225




                3,2111225



























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