Not able to catch error for .on() in firebase












0















I am using below code to retrieve a value



try {
discountFbRef.orderByChild('discode').equalTo(code).on("value", function(snapshot) {
console.log('snapshot val discode', snapshot.val().discode);

if (snapshot.exists()) {
snapshot.forEach(function(data) {

$scope.discountApplicable.id = data.val().id;


});
} else {
console.log('It doesnt exist');
}
}, function(error) {
console.log(error);
});
} catch (error) {
console.log('error occured during search', error);
}


When there is value equal to the search string it's working fine. But when I try to find a keyword that doesn't exist in "discode", It throws




Uncaught TypeError: Cannot read property 'discode' of null




For some reason even though I try to catch the error with try-catch and error function I am not able to catch it.
I need a way to handle the error and show message that search string doesn't exist.










share|improve this question





























    0















    I am using below code to retrieve a value



    try {
    discountFbRef.orderByChild('discode').equalTo(code).on("value", function(snapshot) {
    console.log('snapshot val discode', snapshot.val().discode);

    if (snapshot.exists()) {
    snapshot.forEach(function(data) {

    $scope.discountApplicable.id = data.val().id;


    });
    } else {
    console.log('It doesnt exist');
    }
    }, function(error) {
    console.log(error);
    });
    } catch (error) {
    console.log('error occured during search', error);
    }


    When there is value equal to the search string it's working fine. But when I try to find a keyword that doesn't exist in "discode", It throws




    Uncaught TypeError: Cannot read property 'discode' of null




    For some reason even though I try to catch the error with try-catch and error function I am not able to catch it.
    I need a way to handle the error and show message that search string doesn't exist.










    share|improve this question



























      0












      0








      0








      I am using below code to retrieve a value



      try {
      discountFbRef.orderByChild('discode').equalTo(code).on("value", function(snapshot) {
      console.log('snapshot val discode', snapshot.val().discode);

      if (snapshot.exists()) {
      snapshot.forEach(function(data) {

      $scope.discountApplicable.id = data.val().id;


      });
      } else {
      console.log('It doesnt exist');
      }
      }, function(error) {
      console.log(error);
      });
      } catch (error) {
      console.log('error occured during search', error);
      }


      When there is value equal to the search string it's working fine. But when I try to find a keyword that doesn't exist in "discode", It throws




      Uncaught TypeError: Cannot read property 'discode' of null




      For some reason even though I try to catch the error with try-catch and error function I am not able to catch it.
      I need a way to handle the error and show message that search string doesn't exist.










      share|improve this question
















      I am using below code to retrieve a value



      try {
      discountFbRef.orderByChild('discode').equalTo(code).on("value", function(snapshot) {
      console.log('snapshot val discode', snapshot.val().discode);

      if (snapshot.exists()) {
      snapshot.forEach(function(data) {

      $scope.discountApplicable.id = data.val().id;


      });
      } else {
      console.log('It doesnt exist');
      }
      }, function(error) {
      console.log(error);
      });
      } catch (error) {
      console.log('error occured during search', error);
      }


      When there is value equal to the search string it's working fine. But when I try to find a keyword that doesn't exist in "discode", It throws




      Uncaught TypeError: Cannot read property 'discode' of null




      For some reason even though I try to catch the error with try-catch and error function I am not able to catch it.
      I need a way to handle the error and show message that search string doesn't exist.







      javascript firebase firebase-realtime-database error-handling






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 22 '18 at 2:44









      zynkn

      3,92321030




      3,92321030










      asked Nov 22 '18 at 2:40









      VamsigaVamsiga

      33




      33
























          1 Answer
          1






          active

          oldest

          votes


















          0














          So, the functions that are passed to the second and third parameters of .on are called a callback functions. That means they might get called after (asynchronously) the code you've posted has executed. You'll want to move your try-catch inside of the callback function.



          function handleValueSuccess(snapshot) {
          try {
          console.log('snapshot val discode', snapshot.val().discode);

          if (snapshot.exists()) {
          snapshot.forEach(function(data) {
          $scope.discountApplicable.id = data.val().id;
          });
          } else {
          console.log("It doesn't exist");
          }
          } catch (error) {
          console.log('error occurred during search', error);
          }
          }

          function handleValueError(error) {
          console.log('error occurred on value', error);
          }

          discountFbRef
          .orderByChild('discode')
          .equalTo(code)
          .on("value", handleValueSuccess, handleValueError);





          share|improve this answer


























          • I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

            – Vamsiga
            Nov 22 '18 at 4:42













          • @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

            – Matthew Herbst
            Nov 22 '18 at 4:51






          • 1





            Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

            – Vamsiga
            Nov 22 '18 at 5:00











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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0














          So, the functions that are passed to the second and third parameters of .on are called a callback functions. That means they might get called after (asynchronously) the code you've posted has executed. You'll want to move your try-catch inside of the callback function.



          function handleValueSuccess(snapshot) {
          try {
          console.log('snapshot val discode', snapshot.val().discode);

          if (snapshot.exists()) {
          snapshot.forEach(function(data) {
          $scope.discountApplicable.id = data.val().id;
          });
          } else {
          console.log("It doesn't exist");
          }
          } catch (error) {
          console.log('error occurred during search', error);
          }
          }

          function handleValueError(error) {
          console.log('error occurred on value', error);
          }

          discountFbRef
          .orderByChild('discode')
          .equalTo(code)
          .on("value", handleValueSuccess, handleValueError);





          share|improve this answer


























          • I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

            – Vamsiga
            Nov 22 '18 at 4:42













          • @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

            – Matthew Herbst
            Nov 22 '18 at 4:51






          • 1





            Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

            – Vamsiga
            Nov 22 '18 at 5:00
















          0














          So, the functions that are passed to the second and third parameters of .on are called a callback functions. That means they might get called after (asynchronously) the code you've posted has executed. You'll want to move your try-catch inside of the callback function.



          function handleValueSuccess(snapshot) {
          try {
          console.log('snapshot val discode', snapshot.val().discode);

          if (snapshot.exists()) {
          snapshot.forEach(function(data) {
          $scope.discountApplicable.id = data.val().id;
          });
          } else {
          console.log("It doesn't exist");
          }
          } catch (error) {
          console.log('error occurred during search', error);
          }
          }

          function handleValueError(error) {
          console.log('error occurred on value', error);
          }

          discountFbRef
          .orderByChild('discode')
          .equalTo(code)
          .on("value", handleValueSuccess, handleValueError);





          share|improve this answer


























          • I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

            – Vamsiga
            Nov 22 '18 at 4:42













          • @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

            – Matthew Herbst
            Nov 22 '18 at 4:51






          • 1





            Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

            – Vamsiga
            Nov 22 '18 at 5:00














          0












          0








          0







          So, the functions that are passed to the second and third parameters of .on are called a callback functions. That means they might get called after (asynchronously) the code you've posted has executed. You'll want to move your try-catch inside of the callback function.



          function handleValueSuccess(snapshot) {
          try {
          console.log('snapshot val discode', snapshot.val().discode);

          if (snapshot.exists()) {
          snapshot.forEach(function(data) {
          $scope.discountApplicable.id = data.val().id;
          });
          } else {
          console.log("It doesn't exist");
          }
          } catch (error) {
          console.log('error occurred during search', error);
          }
          }

          function handleValueError(error) {
          console.log('error occurred on value', error);
          }

          discountFbRef
          .orderByChild('discode')
          .equalTo(code)
          .on("value", handleValueSuccess, handleValueError);





          share|improve this answer















          So, the functions that are passed to the second and third parameters of .on are called a callback functions. That means they might get called after (asynchronously) the code you've posted has executed. You'll want to move your try-catch inside of the callback function.



          function handleValueSuccess(snapshot) {
          try {
          console.log('snapshot val discode', snapshot.val().discode);

          if (snapshot.exists()) {
          snapshot.forEach(function(data) {
          $scope.discountApplicable.id = data.val().id;
          });
          } else {
          console.log("It doesn't exist");
          }
          } catch (error) {
          console.log('error occurred during search', error);
          }
          }

          function handleValueError(error) {
          console.log('error occurred on value', error);
          }

          discountFbRef
          .orderByChild('discode')
          .equalTo(code)
          .on("value", handleValueSuccess, handleValueError);






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 23 '18 at 17:50

























          answered Nov 22 '18 at 2:47









          Matthew HerbstMatthew Herbst

          10.9k134688




          10.9k134688













          • I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

            – Vamsiga
            Nov 22 '18 at 4:42













          • @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

            – Matthew Herbst
            Nov 22 '18 at 4:51






          • 1





            Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

            – Vamsiga
            Nov 22 '18 at 5:00



















          • I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

            – Vamsiga
            Nov 22 '18 at 4:42













          • @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

            – Matthew Herbst
            Nov 22 '18 at 4:51






          • 1





            Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

            – Vamsiga
            Nov 22 '18 at 5:00

















          I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

          – Vamsiga
          Nov 22 '18 at 4:42







          I moved them to the call back function it didn't catch errors. I'm not sure how would it work because there is a console.log() inside the call back it doesn't log anything. May be I did something wrong could you show the code based on my code?

          – Vamsiga
          Nov 22 '18 at 4:42















          @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

          – Matthew Herbst
          Nov 22 '18 at 4:51





          @Vamsiga I edited my answer to show what I was thinking. Does that not work for you?

          – Matthew Herbst
          Nov 22 '18 at 4:51




          1




          1





          Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

          – Vamsiga
          Nov 22 '18 at 5:00





          Thanks it worked, I put try catch after the console.log() which is doing the snapshot.val().discode.

          – Vamsiga
          Nov 22 '18 at 5:00




















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