Laravel error: Variable undefined in Blade template (4 solutions)

The Error

The ‘Variable undefined in Blade template’ error is a common issue faced by developers working with the Laravel framework. This error occurs when a variable is referenced in a Blade template, but it has not been passed correctly from the controller or is not defined within the Blade file.

Understanding and fixing this error is crucial for a seamless development experience. Let’s explore some solutions to resolve this error effectively.

Solutions

Solution 1: Ensure Variable Passing from Controller

The most common reason for an undefined variable error in a Blade template is that the variable was not passed to the view from the controller. What we need to do are:

• Inspect the controller method responsible for rendering the view.
• Make sure to pass the variable to the view using the with() method or by passing an array.
• Verify that the variable name matches the one used in the Blade template.

Example:

// In the Controller
public function show($id)
{
    $item = Item::find($id);
    // Pass the variable 'item' to the view
    return view('item.show')->with('item', $item);
}

// In the Blade Template
<h1>{{ $item->name }}</h1>

Notes: This method ensures that the required variable is available in the view. However, remember to check the variable names for typos and to confirm that the variable is not null or empty.

Solution 2: Use the Blade @isset Directive

The @isset directive checks if a variable is set and renders the enclosed code only if the variable exists:

• Wrap the variable in an @isset ... @endisset block in the Blade template.
• This method prevents errors by only executing the block if the variable is defined.

Example:

// In the Blade Template
@isset($item)
    <h1>{{ $item->name }}</h1>
@endisset

Notes: This solution provides a safeguard but does not address the root cause if the variable should have been passed from the controller. Use it when a variable might optionally be passed to the view.

Solution 3: Define a Default Value with the @php Directive

The Blade @php directive allows you to execute PHP code directly within a Blade template. You can define a default value for a variable to avoid the undefined error:

• Use @php at the start of the Blade file to define a default value.
• This step specifies a fallback value in case the variable is not provided.

Example:

// In the Blade Template
@php
    $item = $item ?? 'Default Value';
@endphp
<h1>{{ $item }}</h1>

Notes: Overusing the @php directive can make your templates less readable and goes against the MVC pattern best practices. Use it sparingly for simple defaulting or small calculations.

Solution 4: Check for Variable Existence with PHP isset()

Using the native PHP isset() function you can determine if a variable is defined before attempting to use it:

• Before using the variable in the Blade template, surround it with a PHP isset() call.
• This ensures the variable is displayed only if it exists, preventing the error.

Example:

// In the Blade Template
<?php if(isset($item)): ?>
    <h1>{{ $item->name }}</h1>
<?php endif; ?>

Notes: This technique uses plain PHP, making the template less