Accessing old input values in Laravel is a common practice for maintaining form data across page reloads, especially after validation failures. Laravel provides built-in support for preserving and redisplaying user input to enhance the user experience.

Why Access Old Input Values?

When a user submits a form and validation fails, Laravel redirects them back to the form page, typically including old input values in the session. This allows users to correct their input without having to re-enter all of it.

How to Access Old Input Values

Laravel provides several methods to access old input values in your Blade templates.

1. Using the old Helper

The old helper function retrieves the old input value for a given field name. You can use it to repopulate form fields with previously entered data.

Example:

<form method="POST" action="/submit">
    @csrf

    <label for="name">Name:</label>
    <input type="text" name="name" id="name" value="{{ old('name') }}">

    <label for="email">Email:</label>
    <input type="email" name="email" id="email" value="{{ old('email') }}">

    <button type="submit">Submit</button>
</form>

In this example, if the form submission fails, the old('name') and old('email') functions will repopulate the name and email fields with the previously entered values.

2. Default Values with old

You can provide a default value to the old function if no old input is available. This is useful for pre-filling fields with default values or for new forms.

Example:

<input type="text" name="name" value="{{ old('name', 'Default Name') }}">

In this example, if no old input is available for the name field, it will default to "Default Name".

3. Handling Array Inputs

If your form has fields that are arrays (e.g., multiple checkbox options), you can access old input values for array fields using the old helper with an array notation.

Example:

@foreach ($options as $option)
    <input type="checkbox" name="options[]" value="{{ $option->id }}"
        {{ in_array($option->id, old('options', [])) ? 'checked' : '' }}>
    <label>{{ $option->name }}</label>
@endforeach

In this example, the old('options', []) function checks if each checkbox value was previously selected and maintains the state accordingly.

4. Preserving Old Input for Multiple Fields

If you need to handle complex forms with many fields, using old helps maintain values for all fields after a failed submission.

Example:

<form method="POST" action="/submit">
    @csrf

    <label for="username">Username:</label>
    <input type="text" name="username" id="username" value="{{ old('username') }}">

    <label for="email">Email:</label>
    <input type="email" name="email" id="email" value="{{ old('email') }}">

    <label for="password">Password:</label>
    <input type="password" name="password" id="password" value="{{ old('password') }}">

    <button type="submit">Submit</button>
</form>

In this example, old input values for username, email, and password will be preserved if validation fails.

Handling Old Input in Other Scenarios

**1. Custom Input Processing

Sometimes, you might need to handle input fields that require specific formatting or processing. You can still use the old helper and apply additional logic as needed.

Example:

@php
    $date = old('date') ? old('date') : '2024-01-01';
@endphp

<input type="date" name="date" value="{{ $date }}">

In this example, a default date is set if no old input value is available.

Summary

Accessing old input values in Laravel is a key feature for improving user experience by maintaining form data across page reloads. Using the old helper function in Blade templates allows you to repopulate form fields with previously entered data after validation failures. This practice ensures users do not lose their input and can correct any mistakes more efficiently.