[javascirpt] Regex

function toCurrency(price){
return price.toString().replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,");
}

function deleteValues(array, pred) {
var i = 0,
lng  = array.length;

for(i = lng; i >=0; i--){
if(pred(array[i])){
array.splice(i, 1);
}
}

return array;
}

function candies(kids){
if (kids.length < 2) return -1;

var max = Math.max.apply(null, kids);
var extraCandies = kids.reduce(function (total, kid) {
return total + max - kid;
}, 0);
return extraCandies;
}

function searchNames( logins ){
var failedLogin;
failedLogin = logins.filter(function(login){
return login[0].substr(login[0].length - 1) === '_';
});

return failedLogin;
}

Array.prototype.numberOfOccurrences = function(search) {
return this.filter( function(num){ return search === num } ).length;
}

var Warrior = function(name){
this.name = name;
this.health = 100;
}

Warrior.prototype.strike = function(enemy, swings){
enemy.health = Math.max(0, enemy.health - (swings * 10));
}

function isDivisible(firstN, ...otherN){
return otherN.every(n => firstN % n === 0);
}

Stop gninnipS My sdroW!:

function spinWords(str){
//TODO Have fun :)
var words = str.split(' ');
var s = words.map( (word) => {
if(word.length >= 5){
word = word.split('').reverse().join('');
console.log(word);
}

return word;
}).join(' ');