JSFiddle - React, Tailwind, and code Playground

JavaScript

var inputs = [
    'helloworld',
    'hellloworld',
    'aaabc',
    'abcddd',
    'bbabba'  
];

var violators = [];
inputs.forEach(function(input) {
    if (/(.)\1\1/.test(input)) {
        violators.push(input);
    }
});

alert("VIOLATORS:\n" + violators.join('\n'));