Error on inequality value in blade template Laravel

Question

I'm currently using javascript code on my blade.php (Laravel) page and I have a strange error: My != is not accepted:

if({{ $CurrentProduct->disposable_quantity }} != null) {
    if (newQty > {{ $CurrentProduct->disposable_quantity }}) {
        $('input[name="quantity"]').val({{ $CurrentProduct -> disposable_quantity }});
    }
}

If I put a == my code no longer contains errors. I don't understand

check browser logs... and share it here .... what are logs... this is not fully cleared — Gaurav Bhardwaj, Aug 03 '20 at 14:58
Checking for not null in JS can be weird you may need !== https://stackoverflow.com/questions/4361585/how-to-check-if-a-variable-is-not-null — Uuuuuumm, Aug 03 '20 at 14:59
I only have Uncaught SyntaxError: Unexpected token '!=' @GauravBhardwaj — dolor3sh4ze, Aug 03 '20 at 15:01
What's the output of `{{ $CurrentProduct->disposable_quantity }}`? — Mosh Feu, Aug 03 '20 at 15:11
If that doesn't do the trick, then you could leave out the null altogether and negate the variable, if ( !{{ $CurrentProduct->disposable_quantity }} ) {...} — Uuuuuumm, Aug 03 '20 at 15:18
Seems like there is a case which `{{ $CurrentProduct->disposable_quantity }}` render nothing so the `if` statement looks something like `if (== null)` which throws `Uncaught SyntaxError: Unexpected token '=='` — Mosh Feu, Aug 03 '20 at 15:19

score 1 · Answer 1 · answered Aug 03 '20 at 15:21

1

If you truly want to confirm that a variable is not null and not an empty string specifically, you would write :

if({{ $CurrentProduct->disposable_quantity }} !== null) {
   // do something
}

I changed your code to check for type equality (!==|===).
You can also use below simple code :

if(Boolean({{ $CurrentProduct->disposable_quantity }} )){ 
  // do something 
}

Note : Values that are intuitively empty, like 0, an empty string, null, undefined, and NaN, become false
Other values become true

answered Aug 03 '20 at 15:21

STA

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Is casting to Boolean really necessary? – Uuuuuumm Aug 03 '20 at 15:24
@Uuuuuumm that's an alternative. There are a lot of alternative way like `if (data) { // do something }` – STA Aug 03 '20 at 16:06

Error on inequality value in blade template Laravel

1 Answers1