Laravelで$errorが未定義と表示されます。

Question

Routeを定義している”web.php”でバリテーションを作成して、入力条件にあてはまらなかった場合は、”errors.blade.php”でエラー出力するようにしたいのですが、上手く”errors.blade.php”は呼出せているのですが、そこで以下のようなエラーが出力されます。

Undefined variable: error (View: C:\Users\〇〇〇\laravel\blog\resources\views\common\errors.blade.php)

解決策を教えていただきたいです。

---

試してみたこと

Laravel5.2からは、以下のコードでRouteを囲むべきだそうで、それを行いました。

Route::group(['middleware' => ['web']], function () {
省略
}

<?php
//use Illuminate\Support\Facades\Route;
use App\Book;
use Illuminate\Http\Request;


Route::group(['middleware' => ['web']], function () {
/*==============================================================================
本のダッシュボード表示
===============================================================================*/
Route::get('/', function () {
    $books = Book::orderBy('created_at', 'asc')->get();
    return view('books', [
        'books' => $books
    ]);
});

/*==============================================================================
新しい本の追加
===============================================================================*/

Route::post('/books', function (Request $request){
  //入力のエラー処理
  $validator = Validator::make($request->all(),[
    'item_name' => 'required|max:255',
    'item_number' => 'required|min:3 |max:255',
  ]);

  if($validator->fails()){
    return redirect('/')
      ->withInput()
      ->withErrors($validator);
  }

  //Eloquentモデル
  $books = new Book;
  $books->item_name = $request->item_name;
  $books->item_number = $request->item_number;
  $books->item_amount = '1000';
  $books->published = '2017-03-07 00:00:00';
  $books->save();
  return redirect('/');  // /(ルート)にリダイレクト
});

});

/*
|
| 本を削除
|
*/

Route::delete('/book/{book}', function(Book $book){
    $book -> delete();
    return redirect('/');
});

Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');

<?php

namespace App\Http;

use Illuminate\Foundation\Http\Kernel as HttpKernel;

class Kernel extends HttpKernel
{
    /**
     * The application's global HTTP middleware stack.
     *
     * These middleware are run during every request to your application.
     *
     * @var array
     */
    protected $middleware = [
        \App\Http\Middleware\TrustProxies::class,
        \Fruitcake\Cors\HandleCors::class,
        \App\Http\Middleware\CheckForMaintenanceMode::class,
        \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
        \App\Http\Middleware\TrimStrings::class,
        \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,
    ];

    /**
     * The application's route middleware groups.
     *
     * @var array
     */
    protected $middlewareGroups = [
        'web' => [
            \App\Http\Middleware\EncryptCookies::class,
            \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
            \Illuminate\Session\Middleware\StartSession::class,
            // \Illuminate\Session\Middleware\AuthenticateSession::class,
            \Illuminate\View\Middleware\ShareErrorsFromSession::class,
            \App\Http\Middleware\VerifyCsrfToken::class,
            \Illuminate\Routing\Middleware\SubstituteBindings::class,
        ],

        'api' => [
            'throttle:60,1',
            \Illuminate\Routing\Middleware\SubstituteBindings::class,
        ],
    ];

    /**
     * The application's route middleware.
     *
     * These middleware may be assigned to groups or used individually.
     *
     * @var array
     */
    protected $routeMiddleware = [
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class,
        'cache.headers' => \Illuminate\Http\Middleware\SetCacheHeaders::class,
        'can' => \Illuminate\Auth\Middleware\Authorize::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
        'password.confirm' => \Illuminate\Auth\Middleware\RequirePassword::class,
        'signed' => \Illuminate\Routing\Middleware\ValidateSignature::class,
        'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
        'verified' => \Illuminate\Auth\Middleware\EnsureEmailIsVerified::class,
    ];
}

Answer 1

エラー内容がUndefined variable: errorということでerrorっていう変数が見つからないってことですが、画像を見たら

@foreach($errors->all() as $errors)
  <li>{{$error}}</li>
@endforeach

ってなってるので、
<li>{{$error}}</li>を<li>{{$errors}}</li>にするか
@foreach($errors->all() as $errors)を@foreach($errors->all() as $error)にするかじゃないかなぁ