Use Case:

evaluating strings

First Principles:

Using for loop

const repeatStringNumTimes = (str, num) => {
  if (num <= 0) return '';
  let retStr = '';
  for (let i = num; i > 0; i--) retStr += str;

  return retStr;
};

Why I had to learn this

I am currently working through JavaScript Data Structures and Algorithms certification