[Vuejs]-How to merge 2 objects in Laravel and Vue.Js

Solution will be to define relation hasOne like

public function parent()
{
    return $this->hasOne(Category::class,'id','parent_id');
}

And then you can define resource, where you can claim parent’s title using defined relation like below

$this->parent->title

Create you resource using command

php artisan make:resource CategoryResource

Then in your controller you should use resource

use App\Http\Resources\CategoryResource;

and within controller’s action provide response like

$categories = Category::paginate(15);
return CategoryResource::collection($results); // instead of response()->json($categories , 200);

And example how your resource should look like

<?php

namespace App\Http\Resources;

use Illuminate\Http\Resources\Json\JsonResource;

class CategoryResource extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @param  \Illuminate\Http\Request $request
     * @return array
     */
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'title' => $this->title,
            'parent_id' => $this->parent_id,
            'parent_title' => $this->parent->title,
             ...
        ];
    }
}

Info about resources you can find https://laravel.com/docs/5.8/eloquent-resources

This is code of controller

public function index()
{
    $result = ['success' => true];

    $category = Category::paginate(15);
    $result['category'] = $category->items();
    $result['pagination']['currentPage'] = $category->currentPage();
    $result['pagination']['total'] = $category->total();
    $result['pagination']['perPage'] = $category->perPage();
    return response()->json($result, 200);
}

And here is how I want it to be

I think render function adn array processing must be at the Vue Component

This is my Category model code

 public function products()
{
    return $this->hasMany('App/Products');
}

public function parent()
{
    return $this->hasOne(Category::class,'id','parent_id');
}