Track previous attributes on a Laravel model

readme.md

Lifted directly from @SteveTheBauman's tweet because I find myself needing this functionality very frequently https://twitter.com/SteveTheBauman/status/1524865758043553816

Example usage:

User.php

<?php
namespace App\Models;

use App\Concerns\TracksPreviousAttributes;
use Illuminate\Database\Eloquent\Model;

class User extends Model
{
  use TracksPreviousAttributes;
}

<?php
$user = User::create(['email' => 'foo@example.com']);
$user->update(['email' => 'bar@example.com']);

# ['email' => 'foo@example.com', ...]
$user->getPrevious();

# 'foo@example.com'
$user->getPrevious('email');

TracksPreviousAttributes.php

<?php

namespace App\Concerns;

use Illuminate\Database\Eloquent\Model;

trait TracksPreviousAttributes
{
  protected $previous = [];
  
  public static function bootTracksPreviousAttributes()
  {
    static::saving(function (Model $model) {
      $model->previous = $model->getOriginal();
    });
  }
  
  public function getPrevious(string $key = null)
  {
    if ($key !== null) {
      return data_get($this->previous, $key);
    }
    return $this->previous;
  }
}