# Solution to Day 7 of 7 Days of JS

## 5 December 2019

When writing this solution, I realized that I needed a function that returns true if a number is prime. So I wrote that function first:

function isPrime(n){
let i = 2, rem = true;
while (i < n && rem){
rem = rem && n % i != 0;
i++;
}
return rem;
}

console.log(isPrime(17))


And once I had that, I was ready to write primesUntil, which you can see here:

function primesUntil(n){
let x = 1, i = 0;
while(i < n){
x++;
if (isPrime(x)){
console.log(x);
i++;
}
}
return 'Those are the first ' + n + ' primes.'
}

console.log(primesUntil(5))


It’s possible to write both functions with for loops instead of while loops. If you are just starting out with loops in JavaScript, you should try to do that.

Any questions? Write a comment!

This is the end of our journey. But don’t worry, I’ll be back soon with more challenges. If you don’t want to miss them, follow me on DEV && Pinterest && Twitter && I have a newsletter! 😊

See you soon!