javascript prime numbers up till a certain number

// prime numbers from zero up till a certain number
const sumPrimes = (num) => {  
  let primes=[];
        // computing prime numbers from 0 uptill a number num
    for (let i = 0; i <= num; i++) {
      let flag = 0;
      // looping through 2 to user input number
      for (let j = 2; j < i; j++) {
        if (i % j == 0) {
          flag = 1;
          break;
        }
      }
      // if number greater than 1 and not divisible by other numbers
      if (i > 1 && flag == 0) {
        primes.push(i); // pushing all prime numbers in this array
      }
    }
    return primes;
}
console.log(sumPrimes(10)) // Expected output: 17