Check if variable exist in laravel's blade directive

Question

I'm trying to create blade directive which echo variable (if variable defined) or echo "no data" if variable undefined.

This is my code in AppServiceProvider.php:

<?php

namespace App\Providers;

use Blade;
use Illuminate\Support\ServiceProvider;


class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Blade::directive('p', function($ex) {
            error_log(print_r($ex,true));
            return '<?php $defined_vars = get_defined_vars(); if(array_key_exists(\''. $ex .'\', $defined_vars) ): echo ' . $ex . ' ; else: echo \'no data\'; endif;?>';
        });
    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

Here is my index.blade.php:

<p class="lead">@p($myvar)</p>

But my directive "p" gives "no data" if variable defined. If I use isset error occurres: Cannot use isset() on the result of an expression (you can use "null !== expression" instead)

How could I check inside directives if variable defined?

So you're saying if(isset($myvar)) doesn't work? – Can Celik May 25 '16 at 01:33 — Can Celik, May 25 '16 at 01:33

score 98 · Accepted Answer · answered Sep 28 '18 at 20:30

98

Blade has a directive to check if a variable is set:

@isset($var)

@endisset

answered Sep 28 '18 at 20:30

sanchezcl

1,210
11
6

4

how do you handle else? – Aderemi Dayo Feb 13 '20 at 09:40
7

Like normal with an `@else` – dsturbid Apr 09 '20 at 10:32

score 33 · Answer 2 · answered Nov 03 '17 at 16:03

33

Try checking if the variable is empty:

@if(empty($myvar))
    <p>Data does not exist</p>
@else
    <p>Your data is here!</p>
@endif

Can also check this thread

answered Nov 03 '17 at 16:03

Connor Leech

18,052
30
105
150

score 26 · Answer 3 · answered Oct 18 '18 at 12:19

26

For Laravel 5.7 onwards use.

{{ $checkvariable ?? 'not-exist' }}

answered Oct 18 '18 at 12:19

George John

2,629
2
21
16

Not true, I'm getting Undefined Variable with this code, using Laravel v7 – Lewis Apr 06 '22 at 07:58

score 21 · Answer 4 · answered Jul 06 '19 at 16:13

21

For Laravel version >=5.7

{{ $value ?? '' }}

For Laravel version <5.7

{{ $value or '' }}

answered Jul 06 '19 at 16:13

Puneet Verma

1,373
2
19
23

score 19 · Answer 5 · answered May 25 '16 at 07:13

19

You can use in Blade functionality for checking isset i.e

{{ $checkvariable or 'not-exist' }}

https://laravel.com/docs/5.2/blade#displaying-data

answered May 25 '16 at 07:13

Ali

752
6
18

1

In future I want to add more complex logics to my directive. For example different style for auth user. So I want just type `p($foo)` in view instead of repeating `{{ $checkvariable or 'not-exist' }}` and logics for auth check. – pupadupa May 25 '16 at 21:16

score 16 · Answer 6 · answered Jul 05 '18 at 08:07

16

The best and cleanest way check if a variable exists in blade:

 {!! !empty($myvariable) ? $myvariable : 'variable does not exist' !!}

answered Jul 05 '18 at 08:07

TechPotter

579
8
14

I had an undefined index in an array and this was the perfect solution. – Chad Oct 13 '18 at 04:24

score 6 · Answer 7 · answered Jan 08 '19 at 09:40

You can do it in few different ways.

Sample-1:

@if( !empty($data['var']))
   {{ $data['var'] }} 
@endif

Sample-2:

{{ $data['var'] or 'no data found' }}

Sample-3: Using ternary operator

<a href="" class="{{ ( ! empty($data['var'] ? $data['var'] : 'no data found') }}">

Kiran Maniya · Answer 8 · 2019-12-03T08:07:04.047

You can use the @isset blade directive to check whether the variable is set or not. Alternatively, if you have the default value for that variable you can directly use it as {{ $vatiable ?? 'default_value' }}. The ?? way is available in Laravel v5.7 onwards.

If you want to check for multiple variables at once, you can do it by applying AND operation to expression as @if(isset($var_one) && isset($var_two)).

There are also other ways (lengthy) using @if directive as @if(isset($variable)) but it's not recommended.

Some developer uses @ symbol for error control in a similar situation. The at-sign (@) is used as error control operator in PHP. When an expression is prepended with the @ sign, error messages that might be generated by that expression will be ignored. If the track_errors feature is enabled, an error message generated by the expression and it will be saved in the variable $php_errormsg. This variable will be overwritten on each error. The use of @ is very bad programming practice as it does not make the error disappear, it just hides them, and it makes debugging a lot worse since we can’t see what’s actually wrong with our code.

score 5 · Answer 9 · answered Jun 17 '20 at 21:21

5

For the last version of Larvael make the variable optional in the blade template. Replace $myvar with {{ $myvar }} with {{ $myvar?? '' }}

answered Jun 17 '20 at 21:21

Mr.Senhaji

395
5
13

score 3 · Answer 10 · answered May 25 '16 at 02:05

3

What are you trying to pass to your custom directive? If it's just a string/int the following should work.

Blade::directive('p', function($expression){
    $output = $expression ? $expression : 'nodata';
    return "<?php echo {$output}; ?>";
});

In Blade Template

@p('Foo')

answered May 25 '16 at 02:05

Jeemusu

10,415
3
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I want to use it like that `@p($subtitle)` in my view. And If I use your solution I got this error: `Undefined variable: subtitle` – pupadupa May 25 '16 at 21:13
@pupadupa Have you passed the $subtitle variable to your view? Sounds like blade can't find your variable. – Jeemusu May 26 '16 at 02:40
this is the problem - check in directives if variable doesn't exist. Is there a way to return 'nodata' from directive, if I didnt pass variable to view? – pupadupa May 26 '16 at 20:35
No, I would assume the error you are receiving is from blade before it even executes the custom directive. – Jeemusu May 27 '16 at 02:12
jeemusu@ it appears in view `Undefined variable: subtitle (View: lp/resources/views/blocks/cover.blade.php) (View: lp/resources/views/blocks/cover.blade.php)` – pupadupa May 27 '16 at 11:02
@pupadupa the problem is that that variable `$subtitle` doesn't exist. You NEED to pass this to your view from your controller. – Jeemusu May 29 '16 at 07:55
jeemusu@ hm... but why I could use not-existed variable in this way `{{ $checkvariable or 'not-exist' }}` but not in directive? I thought that there should be a way to create logics that check if variable not exist (inside directive) – pupadupa May 30 '16 at 22:24
Because blade checks to see if the `or` keyword exists, if it does then it doesn't throw an exception because you are passing it a default value. – Jeemusu May 31 '16 at 01:06

score 3 · Answer 11 · answered Jan 02 '19 at 00:32

3

The @empty directive might be useful:

@empty($var)
   $var is unset or false-y
@endempty

answered Jan 02 '19 at 00:32

crishoj

5,660
4
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score 1 · Answer 12 · answered Aug 16 '20 at 18:03

1

To check if variable exist in Laravel blade directive, do this:

Blade::directive('datetime', function ($value) {
    
    return "<?php echo isset($value) ? ($value)->format('d/m/Y H:i:s') : null; ?>";
    
});

answered Aug 16 '20 at 18:03

JulianoMartins

543
1
8
19

Is there a way to retrieve the value of "$value" automatically without having to pass it from the render. For example just use @something and in the creation of the directive rescue $something – Soy César Mora Jun 24 '22 at 13:49

score 0 · Answer 13 · answered Nov 08 '19 at 13:48

0

If you trying check a bool variable you can use @unless

<input type="text" class="@unless ($variable) d-none @endunless" >

answered Nov 08 '19 at 13:48

rickslayer

29
1

The question is about _existence_ of the variable, not the boolean value. _@unless_ will fail if the variable is not set. – datashaman Jan 27 '20 at 05:55

Check if variable exist in laravel's blade directive

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