Laravel Ajax - 500内部错误

Question

每次尝试发出Ajax请求时，我都会收到500内部错误。根据调试，500错误不会弹出，直到＆＃34; if＆＃34;商店功能中的声明。我不能为我的生活找出原因。当我通过常规发布请求运行代码并丢弃Ajax时，它工作正常。有什么想法吗？：

public function store( Request $request, $project_id ) {
    //current logged in user. 
    $user_id = auth()->user()->id;


    //get all post inputs

    $inputs = $request->all();

    //make sure project ID belongs to current user.  Stop someone from adding a task to your project that isn't you. 
    $projectBelongsToUser = Project::find(1)->where('user_id', $user_id)->where('id', $project_id);



    //if a project ID and inputs are provided - log them to the database, if not redirect to home with $errors. 
    if( $project_id && $inputs['submit'] && $projectBelongsToUser ) {

        $task = New Task;

        $task->description = $inputs['description'];
        $task->due_date = $inputs['due_date'];
        $task->priority = $inputs['priority'];
        $task->completed = 0;
        $task->order = 0;
        $task->user_id = $user_id;
        $task->project_id = $project_id;
        $task->save();

        //get all tasks
        $tasks = Task::all();

        //sanitize tasks for safe output
        function sanitize_object_h( $array ) {
            $array_modified = $array;

            foreach( $array_modified as $object ) {
                foreach( $object as &$item ) {
                    $item = htmlentities( $item, ENT_QUOTES );
                }
                //end foreach
            }
            //end foreach
            return $array_modified;
        }
        //end sanitize_object_h

        $sanitized_tasks = sanitize_object_h( $tasks );

        //return the sanitized object. 
        echo json_encode( $sanitized_tasks );
        // return redirect( '/tasks/' . $project_id );

    } else {

        echo "failed";
        return;

    }//end if



}//end store

JavaScript的：

function postData( form, url ) {
    var returnData;
    console.log("form data  " + form.serialize());
    $.ajaxSetup({
      headers: {
        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
      }
    });

    $.ajax({
        url: url,
        type:"POST",
        data: form.serialize(),
        success:function(data){
            console.log(data);
        },error:function(data){ 
            console.log(data);
        }
    }); //end of ajax


    return returnData;
}//end postData

头脑中的HTML：

<meta name="csrf-token" content="{{ csrf_token() }}">