prime numbers

prime.ts

function* primeNumbers() {
  const primeList = [2, 3];
  let nextCandidate = 4;

  yield 1;
  yield 2;
  yield 3;

  while(true) {
    if(primeList.every(prime => nextCandidate % prime !== 0)) {
      yield nextCandidate;
      primeList.push(nextCandidate);
    }
    nextCandidate++;
  }
}

function isPrime(n: number): boolean {
  if (n <= 0) {
    return false;
  }

  if (n <= 3) {
    return true;
  }

  let i = 2;

  while (i <= Math.sqrt(n)) {
    if (n % i === 0) {
      return false;
    }
    i++;
  }

  return true;
}

function getPrimeWithDigits(maxDigits: number): number {
  let primeDigits = 0;
  let num = 1;

  while (true) {
    const isPrimeNumber = isPrime(num);

    if (isPrimeNumber) {
      primeDigits += num.toFixed(0).length;

      if (primeDigits >= maxDigits) {
        break;
      }
    }

    num++;
  }

  return num;
}

// Tests
[1_000].forEach((num) => {
  const primeWithDigits = getPrimeWithDigits(num);
  console.log(`primeDigits: num=${num} ouput=${primeWithDigits}`);
});