Find the prime factors of a number in JavaScript
The prime factors of a number are the prime numbers that divide the number exactly. An easy way to find the prime factors of a number is using trial division, which is a simple algorithm that checks each possible prime factor in order.
This algorithm is not efficient for large numbers, as it has a high time complexity. You should look into more efficient algorithms for prime factorization, if you plan to implement this in a production environment.
Implementing the algorithm is straightforward. You can use a while loop to iterate over all possible prime factors, starting with 2. If the current factor, f, exactly divides n, add f to the factors array and divide n by f. Otherwise, increment f by one.
const primeFactors = n => {
let a = [],
f = 2;
while (n > 1) {
if (n % f === 0) {
a.push(f);
n /= f;
} else {
f++;
}
}
return a;
};
primeFactors(147); // [3, 7, 7]
