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I refactored my code, even so, I’m still generated the same Error Exception. I will show the old code and the refactored code. I’ll also provided the error message generated by Laravel. in addition to the spaghetti code I received when troubleshooting the error with dd().

I have my own custom made helper functions that I’m using. It’s a class and is injected into the home page Controller as a dependency. My helper function is then passed to Laravel Blade as a variable named helper.

The goal is to have my navigation links change to a different color if it is the currently selected and active link to that page.

When I apply the $helper variable to the first link, I get my desired result. However, the $helper variable generates the Undefined Variable $helper Error Exception on all the other links.

I used dd() to troubleshoot the error. I received a output of spaghetti code as a result.

Utilities/Helper class example – my custom helper function


/*
* Original
*/

<?php

namespace AppUtilities;

class Helper
{
  public static function activePage(string $pageUrl): string
  {
    $requestUri = $_SERVER['REQUEST_URI'];
    
    return $requestUri === $pageUrl ? "color=var(--sky)" : "color=var(--mud)";   
  }
}

/*
* Refactored
*/

<?php

namespace AppUtilities;

class Helper
{
  public static function activePage(string $pageUrl): string
  {    
    return Request::is($pageUri) ? "style=color:var(--sky)" : "style=color:var(--mud)";   
  }
}

Controller/Home Action example


<?php

namespace AppHttpControllers;

use AppHttpControllersBaseController;
use AppUtilitiesHelper;
use IlluminateViewView;

class Home extends BaseController
{

  public function __construct(
   private Helper $helper,  
  ){}

  public function index(): View
  {
    return view('home', [
      'helper' => $this->helper::class,
    ]);
  }
}

Laravel Blade Template home page example


<!-- Original -->

<li class="nav-links">        
  <a href="{{ url('/') }}"         style="{{ $helper::activePage('/') }}">Home</a>
  <a href="{{ url('/services') }}" style="{{ $helper::activePage('/services') }}">Services</a>
  <a href="{{ url('/clients') }}"  style="{{ $helper::activePage('/clients') }}">Clients</a>
  <a href="{{ url('/about') }}"    style="{{ $helper::activePage('/about') }}">About</a>
  <a href="{{ url('/blog') }}"     style="{{ $helper::activePage('/blog') }}">Blog</a>
  <a href="{{ url('/contact') }}"  style="{{ $helper::activePage('/contact') }}" class="contact-link">Contact</a>
</li>

<!-- Refactored -->

<li class="nav-links">        
  <a href="{{ url('/') }}"         {{ $helper::activePage('/') }}>Home</a>
  <a href="{{ url('/services') }}" {{ $helper::activePage('/services') }}>Services</a>
  <a href="{{ url('/clients') }}"  {{ $helper::activePage('/clients') }}>Clients</a>
  <a href="{{ url('/about') }}"    {{ $helper::activePage('/about') }}>About</a>
  <a href="{{ url('/blog') }}"     {{ $helper::activePage('/blog') }}>Blog</a>
  <a href="{{ url('/contact') }}"  {{ $helper::activePage('/contact') }} class="contact-link">Contact</a>
</li>

<!-- Also tried: no error occurred, but was not able to get the color to change to var(--sky) on the second link -->

<li class="nav-links">        
  <a href="{{ url('/') }}" {{ Request::is('/') ? "style=color:var(--sky)" : "style=color:var(--mud)" }}>Home</a>
  <a href="{{ url('/services') }}" {{ Request::is('/services') ? "style=color:var(--sky)" : "style=color:var(--mud)" }}>Services</a>
  <a href="{{ url('/clients') }}">Clients</a>
  <a href="{{ url('/about') }}">About</a>
  <a href="{{ url('/blog') }}">Blog</a>
  <a href="{{ url('/contact') }}" class="contact-link">Contact</a>
</li>

Image of Error Exception

Laravel Error Message

Laravel Error Code

Generated unformatted spaghetti code when using dd()


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'▶' : '▼'; a.className += ' sf-dump-toggle'; x = 1; if ('sf-dump' != elt.parentNode.className) { x += elt.parentNode.getAttribute('data-depth')/1; } } else if (/bsf-dump-refb/.test(elt.className) && (a = elt.getAttribute('href'))) { a = a.slice(1); elt.className += ' sf-dump-hover'; elt.className += ' '+a; if (/[[{]$/.test(elt.previousSibling.nodeValue)) { a = a != elt.nextSibling.id && doc.getElementById(a); try { s = a.nextSibling; elt.appendChild(a); s.parentNode.insertBefore(a, s); if (/^[@#]/.test(elt.innerHTML)) { elt.innerHTML += ' ▶'; } else { elt.innerHTML = '▶'; elt.className = 'sf-dump-ref'; } elt.className += ' sf-dump-toggle'; } catch (e) { if ('&' == elt.innerHTML.charAt(0)) { elt.innerHTML = '…'; elt.className = 'sf-dump-ref'; } } } } } if (doc.evaluate && Array.from && root.children.length > 1) { root.setAttribute('tabindex', 0); SearchState = function () { this.nodes = []; this.idx = 0; }; SearchState.prototype = { next: function () { if (this.isEmpty()) { return this.current(); } this.idx = this.idx < (this.nodes.length - 1) ? this.idx + 1 : 0; return this.current(); }, previous: function () { if (this.isEmpty()) { return this.current(); } this.idx = this.idx > 0 ? this.idx - 1 : (this.nodes.length - 1); return this.current(); }, isEmpty: function () { return 0 === this.count(); }, current: function () { if (this.isEmpty()) { return null; } return this.nodes[this.idx]; }, reset: function () { this.nodes = []; this.idx = 0; }, count: function () { return this.nodes.length; }, }; function showCurrent(state) { var currentNode = state.current(), currentRect, searchRect; if (currentNode) { reveal(currentNode); highlight(root, currentNode, state.nodes); if ('scrollIntoView' in currentNode) { currentNode.scrollIntoView(true); currentRect = currentNode.getBoundingClientRect(); searchRect = search.getBoundingClientRect(); if (currentRect.top < (searchRect.top + searchRect.height)) { window.scrollBy(0, -(searchRect.top + searchRect.height + 5)); } } } counter.textContent = (state.isEmpty() ? 0 : state.idx + 1) + ' of ' + state.count(); } var search = doc.createElement('div'); search.className = 'sf-dump-search-wrapper sf-dump-search-hidden'; search.innerHTML = ' 
 0 of 0</span>

After reading the code, is there anything you think would cause an error to occur?

2

Answers


  1. Chosen as BEST ANSWER

    The Solution to Laravel Undefined Variable Error Exception. To keep it very simple. Each controller renders a view. So if you're working on the home page nav links and each controller renders a view for each of those links. You'll receive an Error Exception if you try to echo a variable on the other links and missing the fact that you didn't passed the variable through your other controllers first. I'll provide code examples below.

    Helper Function / Dependency

    
    class helper
    {
      public static function pleaseHelp(string $param): string
      {
        return // your code
      }
    }
    
    

    Controllers

    
    namespace AppControllers;
    
    use AppUtilitiesHelper;
    
    // The variable 'set' works on the rendered home page and the home nav link.
    // It will not work on the other nav links without causing the Error Exception.
     
    class Home
    {
      public function __construct(
        private Helper $pleaseHelp,
      ){}
      
      public function index(): View
      {
        return view('home', [
          'set' => $this->pleaseHelp,
        ]);
      }
    }
    
    // In order to get your nav links working on the other pages, you'll need
    // to inject your Helper Dependency into your other controller class.
      
    class About
    {
      // Helper Dependency here...
    
      return view('about', [
        'set' => $this->pleaseHelp,
      ]);
    }
    
    class Contact
    {
      // Helper Dependency here too...
    
      return view('contact', [
        'set' => $this->pleaseHelp,
      ]);
    }
    
    

    Laravel Blade / html

    
    // Link about & contact can now read the variable $set and load the page without error
    <nav>
      <a href="{{ url('/') }}" class="{{ $set::pleaseHelp('/') }}">Home</a>
      <a href="{{ url('about') }}" class="{{ $set::pleaseHelp('about') }}">About</a>
      <a href="{{ url('contact') }}" class="{{ $set::pleaseHelp('contact') }}">Contact</a>
    </nav>
    
    

  2. You never use $_SERVER in Laravel.

    Read the entire documentation page. It’s part of Laravel’s standard functionality.

    <a href="{{ url('/') }}" style="@if(request()->is('/'))
     ... 
    @else 
     ...
    @endif">Home</a>
    

    It is recommended that you start by using Breeze to learn the Laravel.

    https://github.com/laravel/breeze/blob/2.x/stubs/default/resources/views/components/nav-link.blade.php

    https://github.com/laravel/breeze/blob/2.x/stubs/default/resources/views/layouts/navigation.blade.php

    <x-nav-link :href="route('dashboard')" :active="request()->routeIs('dashboard')">
        {{ __('Dashboard') }}
    </x-nav-link>
    

    The current common way to use Laravel is to utilize the Blade component.

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