Cannot assign value to a variable - Javascript

Question

I am having trouble assigning the value of "$scope.returnPollings[i]" to "plrtn" during the loop. "$scope.returnPollings" is an object with a data and i can confirm there is a data in it when i console.log it.

    db.transaction (function(tx) {
        var sql = "INSERT INTO STATUSREPLY (reply, name, userCode, icon, target, repliedDate) VALUES (?, ?, ?, ?, ?, ?)";
        var len = $scope.returnPollings.length;
        var plrtn;                              
        for (var i = 0; i < len; i++) {
            plrtn = $scope.returnPollings[i]; // value is not being assigned here
            tx.executeSql(sql, [plrtn.message, plrtn.name, plrtn.userCode, plrtn.qWink, plrtn.target, plrtn.createdDate ], 
                function(){ 
                        $scope.$apply(function(){
                            $scope.returnFstatus.push({
                                'message':$scope.ie.message, 
                                'createdDate':$scope.ie.createdDate, 
                                'icon':$scope.ie.qWink, 
                                'target':$scope.ie.target 
                                    });
                            })                                  
                    console.log('Status Inserted');
           },function(tx, error) {
                console.log('polling INSERT ERROR: ' + error.message);
                                 });
                            }

});

I will be glad if anyone can help me

is data in JSON or as string, mayb e $.JSON.stringify would help? what is the structure of returnPollings? — changtung, Jan 25 '15 at 19:16
@cyan returnPollings[0].message gives me the value of the message which is "how are they" — David Addoteye, Jan 25 '15 at 19:27
so after assigning what is the value of plrtn.message ? is it "how are they"?if yes, then assignment is fine at the first spot. — changtung, Jan 25 '15 at 19:29
@DavidAddoteye try to use $scope.returnPollings[i] instead of creating a variable plrtn. There might be a problem that executeSql() is asynchronous so JavaScript gets confused after couple of iterations, so the value of the variable is not as expected. — Tome Pejoski, Jan 25 '15 at 19:55
@tomepejo your answer '$scope.returnPollings[i]' instead of creating a variable plrtn also worked. $scope.returnPollings[i]. Thank you guys — David Addoteye, Jan 25 '15 at 20:47

score 1 · Accepted Answer · answered Jan 25 '15 at 19:40

1

The answer is, that you are assigning more than once to the same variable. i would do this like this:

plrtn;//without var
        for (var i = 0; i < len; i++) {
            delete plrtn;
            plrtn = $scope.returnPollings[i]; // value is not being assigned here

answered Jan 25 '15 at 19:40

changtung

1,614
15
19

Just be careful with this implementation. Without var, plrtn will be assigned as variable on the global scope, so that can affect some error in other part of the application. For more details please read the answer to this question: [What is the function of the var keyword and when to use it (or omit it)?](http://stackoverflow.com/questions/1470488/what-is-the-function-of-the-var-keyword-and-when-to-use-it-or-omit-it) – Tome Pejoski Jan 25 '15 at 21:31

Misunderstood · Answer 2 · 2015-01-25T20:26:00.527

Look at the value of $scope.returnPollings

var plrtn;  
console.log($scope.returnPollings);
for (var i = 0; i < len; i++) {

You get two values for $scope.returnPollings[0]
In the Console you should be able to see the two (length) values of
$scope.returnPollings[0] and $scope.returnPollings[1]

Also

$scope.returnPollings[0].message
$scope.returnPollings[0].name
$scope.returnPollings[0].userCode
$scope.returnPollings[0].q

$scope.returnPollings[1].message
$scope.returnPollings[1].name
$scope.returnPollings[1].userCode
$scope.returnPollings[1].q

In your SQL you do not need to use plrtn.

Instead you could use:

$scope.returnPollings[i].message
$scope.returnPollings[i].name
$scope.returnPollings[i].userCode
$scope.returnPollings[i].q

i get the value when i console.log it there. when i console.log $scope.returnPollings.length i get 2 — David Addoteye, Jan 25 '15 at 19:24

Cannot assign value to a variable - Javascript

2 Answers2