The string repeat() method in vanilla JS

In vanilla JavaScript, the string repeat() method lets you—well—repeat a string. I encountered it the other day after completing a challenge on Codewars and seeing others' solutions. I honestly had no idea it existed.

The challenge

"Write a function called repeatStr which repeats the given string str exactly num times."

I swapped the str and num parameters around because I think they make more sense this way: pass in the string, then how many times you want to repeat it.

repeatStr('I', 6); // 'IIIIII'
repeatStr('Hello', 5); // 'HelloHelloHelloHelloHello'

My first solution

Unaware of the repeat() method, my solution was to:

1. Create an array with num empty slots
2. Fill each slot with the given string str
3. Join the values together into a single string

function repeatStr(str, num) {
  return new Array(num).fill(str).join('');
}

Using the repeat() method

My solution worked, but after completeting the challenge and unlocking others' solutions, I learned that I could have just done this:

function repeatStr(str, num) {
  return str.repeat(num);
}

Aside from teaching you about the repeat() method, the purpose of this article is to remind you that you don't have to know everything to be a developer. It's all about being a lifelong learner and knowing what steps to take to solve a problem!

Learn more: The string repeat() method in the MDN Web Docs.