JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
  <li>1</li>
  <li>2</li>
  <li>3</li>
  <li>4</li>
  <li>5</li>
  <li>6</li>
  <li>7</li>
  <li>8</li>
  <li>9</li>
  <li>10</li>
 </ul>

JavaScript

// Anonymous function
(function () {
		var Library = function (params) {
        var selector = document.querySelectorAll(params),
            i = 0;
        this.length = selector.length;
        for (; i < this.length; i++) {
            this[i] = selector[i];
        }
        return this;        
    };
    var Q = function (params) {
        return new Library(params);
    };
    // Assign our Q object to global window object.
    Q.fn = Library.prototype = {
    nth: function( cur, result, dir, elem ) {
        result = result || 1;
        var num = 0;

        for ( ; cur; cur = cur[dir] ) {
          if ( cur.nodeType === 1 && ++num === result ) {
            break;
          }
        }

        return cur;
      },
    	next: function () {
      
      },
      hide: function () {
        var len = this.length;
        while (len--) {
          this[len].style.display = 'none';
        }
        return this;
      },
      show: function () {
        var len = this.length;
        while (len--) {
          this[len].style.display = 'block';
        }
        return this;
      }    
    }; 
    
    if(!window.Q) {
        window.Q = Q;
    }
})();
 console.log(Q("li").hide().show());