Call to a member function store() on null on Livewire - laravel-livewire

Question

I'm new to Livewire and I faced this problem Call to a member function store() on null I don't know how to make the store() function not work when I don't send a file! graduation_certificate it is nullable.
Database file
public function up()
{
Schema::create('user_trainees', function(Blueprint $table) {
$table->increments('id');
$table->integer('user_id')->unsigned();
$table->integer('region_id')->unsigned();
$table->integer('city_id')->unsigned();
$table->integer('university_id')->unsigned();
$table->integer('department_id')->unsigned();
$table->string('major', 150);
$table->bigInteger('student_number')->nullable();
$table->float('gpa');
$table->enum('gpa_type', array('4', '5'));
$table->enum('training_date', array('firstsemester', 'secondsemester', 'thirdsemester', 'summersemester'))->nullable();
$table->integer('training_hours')->nullable();
$table->integer('graduation_year')->nullable();
$table->enum('academic_degree', array('bachelor', 'diploma'));
$table->string('graduation_certificate', 200)->nullable();
$table->string('academic_transaction', 200);
$table->string('cv', 200);
$table->tinyInteger('is_graduate');
$table->timestamps();
$table->softDeletes();
});
}
blade file
<x-form.label label="وثيقة التخرج" name="graduation_certificate" />
<div class="flex">
<input type="file" wire:model="graduation_certificate" name="graduation_certificate"
id="graduation_certificate"
class="px-8 py-12 border-2 border-dashed rounded-md dark:border-gray-700 dark:text-gray-400 dark:bg-gray-800">
</div>
livewire class
public function submit()
{
$user_uni = User::create([
'name' => "{$this->firstName} {$this->lastName}",
'type_id' => $this->userType,
'email' => $this->email,
'password' => bcrypt($this->password),
'gender' => $this->gender,
'mobile' => $this->mobile,
'is_active' => 1,
]);
UserTrainee::create([
'user_id' => $user_uni->id,
'region_id' => $this->region,
'city_id' => $this->city,
'university_id' => $this->university,
'department_id' => $this->department,
'major' => $this->major,
'student_number' => $this->studentNumber,
'gpa' => $this->gpa,
'gpa_type' => $this->gpa_type,
'training_date' => $this->training_date,
'training_hours' => $this->trainingHours,
'graduation_year' => $this->graduation_year,
'academic_degree' => $this->academic_degree,
'graduation_certificate' => $this->graduation_certificate->store('files', 'public'),
'academic_transaction' => $this->academic_transaction->store('files', 'public'),
'cv' => $this->cv->store('files', 'public'),
'is_graduate' => $this->traineeType,
]);
}

Answer 1

You don't conditionally store the files, meaning that even if you haven't uploaded something (meaning its NULL), you attempt to store it. Just wrap some conditions around it,
// ...
'graduation_certificate' => $this->graduation_certificate ? $this->graduation_certificate->store('files', 'public') : null,
'academic_transaction' => $this->academic_transaction ? $this->academic_transaction->store('files', 'public') : null,
'cv' => $this->cv ? $this->cv->store('files', 'public') : null,
// ...

Answer 2

you have to make variable of cv like you made for graduation_certificate, cv is getting NULL that's why you are facing this error