php - Cannot obtain correct Boolean value when sent in ajax

let's say we have the following ajax:

$.ajax({

    url:'myURL.php',
    data:{
        ac:'do',
        isDoable:false
    }
});

Now at the back end when reading the call data, the isDoable is a string, and trying to cast it as Boolean:

$isDoable = (bool) $_REQUEST['isDoable'];

results in $isDoable always being true, even when sent as false.
When I encountered this issue I gave up and simply treated it as a string if($_REQUEST['isDoable'] == 'true')

But I cannot get over it! why is this unexpected behavior, and is there a way around it?

Answer

As you are not sending a JSON data via POST (that could be handle correctly with the json_decode) your string "true" or "false" will always be the boolean true, because PHP will assume that, as a non empty string, your var should be converted to the true boolean value.

So, you should use string comparison instead in your case.

In example:

$value = (bool)"test"; // whatever value, not empty string
var_dump($value);

is the boolean true

$value = (bool)"";
var_dump($value);

is the boolean false