get star length

star.js

var stars = '✮✮✮✮✮✩✩✩✩✩';

var score = function(len) {
  return stars.substring(5 - len, 10 - len)
}

console.log(score(1));
console.log(score(2));
console.log(score(3));
console.log(score(4));
console.log(score(5));