PHP Modular Menu Sidebar Codeigniter & Laravel

modularSidebar.php

<?php
//Controller
    $model = new MUserMenuModel();
    $menu = $model->getMenu($model);
    $data = $model->fetchMenu($menu);

//Model
    public function getMenu($model)
    {
        $menu = $model->where('parent_id', 0)->findAll();
        $i = 0;
        foreach ($menu as $row) {
            $menu[$i]['sub'] = $this->getSubMenu($model, $row['id']);
            $i++;
        }

        return $menu;
    }

    public function getSubMenu($model, $id)
    {
        $menu = $model->where('parent_id', $id)->findAll();
        $i = 0;
        foreach ($menu as $row) {
            $menu[$i]['sub'] = $this->getSubMenu($row['id']);
            $i++;
        }

        return $menu;
    }
    public function fetchMenu($data)
    {
        $menu1 = "";
        foreach ($data as $menu) {
            if (!empty($menu['sub'])) {
                $menu1 .= '<li class="nav-item">
                                <a href="' . ($menu["url"]) . '" class="nav-link" title="'.$menu['description'].'">
                                    <i class="'.$menu['icon'].'"></i> 
                                    <p>' . $menu['title'] . '
                                        <i class="right fas fa-angle-left"></i>
                                    </p>
                                </a>';
                $menu1 .= '<ul class="nav nav-treeview">';
                $menu1 .= $this->fetchSubMenu($menu['sub']);
                $menu1 .= '</ul>';
                $menu1 .= '</li>';
            }else{
                $menu1 .= '<li class="nav-item">
                                <a href="' . ($menu["url"]) . '" class="nav-link" title="'.$menu['description'].'">
                                    <i class="'.$menu['icon'].'"></i> 
                                    <p>' . $menu['title'] . '</p>
                                </a>
                            </li>';
            }
        }

        return $menu1;
    }

    public function fetchSubMenu($sub_menu)
    {
        $sub = "";
        foreach ($sub_menu as $menu) {
            if (!empty($menu['sub'])) {
                $sub .= '<li class="nav-item">
                            <a href="' . ($menu["url"]) . '" class="nav-link" title="'.$menu['description'].'">
                                <i class="'.$menu['icon'].'"></i> 
                                <p>' . $menu['title'] . '
                                    <i class="right fas fa-angle-left"></i>
                                </p>
                            </a>';
                $sub .= '<ul class="nav nav-treeview">';
                $sub .= $this->fetchSubMenu($menu['sub']);
                $sub .= "</ul>";
                $sub .= '</li>';
            }else{
                $sub .= '<li class="nav-item">
                            <a href="' . ($menu["url"]) . '" class="nav-link" title="'.$menu['description'].'">
                                <i class="'.$menu['icon'].'"></i> 
                                <p>' . $menu['title'] . '</p>
                            </a>
                        </li>';
            }
        }

        return $sub;
    }