CODEWITHSUNDEEP
javascriptjqueryboolean-expression
EmmyS
EmmyS

Reputation: 12138

"true" evaluation running even when value is false

I have a very simple piece of jquery that needs to check a boolean value returned from an ajax call and set a checkbox to checked if it's true.

console.log("loc: " + r.location.defaultLocation);
if( r.location.defaultLocation == true ) {
    $('#loc-default').attr('checked',true);
}

This runs in an onclick function that opens a modal form - if the location info that is returned indicates that this is the default location, the checkbox should be checked. We have 5 of these on a single page - i.e. 5 locations the users can click on.

What I'm running into is that even if r.location.defaultLocation returns false (per the console.log line), the checkbox is still being checked. What am I doing wrong?

For those of you who insist that true/false must be a string, rather than a boolean:

This is the result of console.info(typeof(r.location.defaultLocation));

enter image description here

And this is the result of console.dir(r), if it helps. (group is blurred because it's sensitive info.)

enter image description here

FOUND THE ISSUE

Apparently jquery is remembering that #loc-default is checked after the first one was marked checked. I added an else to the function and now it works:

if( r.location.defaultLocation == true ) {
    $('#loc-default').attr('checked',true);
}
else {
    $('#loc-default').attr('checked', false);
}

Upvotes: 3

Views: 258

Answers (5)

Jamie Hutber
Jamie Hutber

Reputation: 28064

First of all i would check to see what r.location.defaultLocation is

 console.info(typeof(r.location.defaultLocation));

Then i would go from there but using above code:

 if (!!r.location.defaultLocation && typeof(r.location.defaultLocation)==="string") {}

Upvotes: 0

Michael
Michael

Reputation: 532

Since your code appears to be correct, I would try handling the else statement and force the checkbox to not be checked.

if( r.location.defaultLocation == true ) {
    $('#loc-default').attr('checked',true);
} else {
    $('#loc-default').attr('checked',false);
}

Upvotes: 1

Magus
Magus

Reputation: 15104

I think r.location.defaultLocation is the string "false". So if you use console.log on it, you will see "false". But "false" == true is true.

You can check the type of a variable with typeof.

console.log(typeof r.location.defaultLocation); // Log the current type of r.location.defaultLocation
console.log(typeof false); // Display boolean
console.log(typeof "false"); // Display string

Upvotes: 2

DNS
DNS

Reputation: 38189

The only way I can see that happening is if defaultLocation is not actually the boolean false, but instead the string "false", which evaluates as true.

Upvotes: 3

drmonkeyninja
drmonkeyninja

Reputation: 8540

Make sure r.location.defaultLocation is a boolean.

Try if (!!r.location.defaultLocation) {} to force the value to be of type boolean.

Upvotes: 2

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