How to import JavaScript files to React Component

Question

I have a web template and a lot of javascript files for design. I want to use this files with React component. I put the javascript files to index.html but its not working.

There is a lot of classes in the html for design, for example:

<h6 className="wow fadeInUp" data-wow-delay=".5s"><span className="text-uppercase id-color-2"> Market</span></h6>

It doesnt shown on the page.

I tried this solution: How to import js file to React component?

But there are a lot of functions, am i gonna add them all? I just import the file to component.

This is a file that i want to import, heres a part of this file:

import {$, jQuery} from 'jquery'; 
 /* --------------------------------------------------
  * © Copyright 2021 - Gigaland by Designesia
  * --------------------------------------------------*/
(function($) {
    'use strict';

     /* predefined vars begin */
     var mobile_menu_show = 0;
     var v_count = '0';
     var mb;
     var instances = [];
     var $window = $(window);
     var $tmp_h = '90';
     var $op_header_autoshow = 0;
     var grid_size = 10;
     /* predefined vars end */
     
     if($('header').hasClass("has-topbar")){
          $tmp_h = '125px';
     }

Any help would be appreciated.