laravel 8 livewire nie dodaje do bazy danych wartosci z inputa

Question

jak w temacie- do bazy danych dodaje pustą wartosc 'body'. jestem amatorem i nie ogarne tego bez Waszej pomocy. (ten  if($this->newPost='') { return; } tez nie dziala bo niby nie powinno nic robic, jak jest pusty, ale dodaje... 

<form  wire:submit.prevent="addPost">
  <input type="text"  wire:model.lazy="newPost">
 <button type="submit">
  Dodaj
</button>
</form>

class Show extends Component
{
public $posts;

public $newPost;

public function mount()
{
    $initPosts=Post::latest()->get();
    $this->posts=$initPosts;
}

public function addPost()
{
    if($this->newPost='')
    {
        return;
    }
    $createdPost = Post::create([
    'body'=>$this->newPost, 'user_id' =>2]);
    $this->posts->prepend($createdPost);
    $this->newPost="";
}

    public function render()
    {
        return view('livewire.posts.show');
    }
}

model Post

class Post extends Model
{
    use HasFactory;
    protected $fillable= ['body', 'user_id'];

    protected $guarded = [];
    public function comments()
    {
        return $this->hasMany('App\Models\Comment');
    }
    public function creator()
    {
        return $this->belongsTo('App\Models\User', 'user_id');
    }

}

migracja posts

  Schema::create('comments', function (Blueprint $table) {
            $table->id();
            $table->text('body');
            $table->foreignId('post_id')
            ->references('id')
            ->on('posts')
            ->onDelete('cascade');
            $table->foreignId('user_id')
            ->references('id')
            ->on('users')
            ->onDelete('cascade');
            $table->timestamps();
        });