Sum All Primes - can't get last test

Tell us what’s happening:

Not sure where this is going wrong. My primeArray seems to only contain prime numbers, and I’ve got sumPrimes(10) working fine. Somehow I’m not getting up to the right total with the last challenge.

Your code so far

function sumPrimes(num) {
  let total = 0;
  let primeArray = [];
  function isPrime(candidate){
    for(let i = 2; i < candidate; i++){
      if(candidate % i === 0){
        return false;
    return true;
  for(let j = 2; j < num; j++){
  total = primeArray.reduce((a,b) => a + b);
  return total;


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Link to the challenge:

Your prime generation algorithm isn’t fast enough and is tripping the infinite loop protection for the final challenge

I wish we had a note about it in the challenge text, or a console message that it’s occurred when it’s tripped (either change could be a good pull request for a beginner)

Consider googling and reading about various prime number generation methods - a particular favourite of mine is the sieve of eratosthenes