JSFiddle - React, Tailwind, and code Playground

JavaScript

Function.prototype.method = function (name, func) {
        if (!this.prototype[name]) {
            this.prototype[name] = func;
        }        
    };
    
    String.method('deentityify', function () {
        
        var entity = {
            quot: '"',
            lt: '<',
            gt: '>'
        };
        
        return function () {
            
            /*if (this === String.prototype) {
                alert('true');
            } else {
                alert('false');
            }*/
            
            return this.replace(/&([^&;]+);/g,
                function (a, b) {
                    var r = entity[b];
                    return typeof r === 'string' ? r : a;
                }
            );
        };
    }());
    
    document.write('&lt;&quot;&gt;'.deentityify());