JSFiddle - React, Tailwind, and code Playground

JavaScript

String.prototype.endsWith = function(str){alert(str);
    return (this.lastIndexOf(str) == this.length - str.length)
        }

var aa='a cat';
var bb='a cat?'; 

if(aa.endsWith('cat')){
    document.write('cat matched'+'<br\/>');
}

if(bb.endsWith('cat?')){
    document.write('cat? matched');
}