Question

How to find the prime factors of a number in JavaScript

Answer 1

function printPrimeFactor(n) {
    let div = 2;
    while (n !== 0) {
        if (n % div !== 0) {
            div = div + 1;
        }
        else {
            console.log(div);
            n = n / div;
            if (n == 1) {
                break;
            }
        }
    }
    console.log("\n");
}

const n = 124;
          
printPrimeFactor(n); // 2 x 2 x 31
printPrimeFactor(288); // 2 x 2 x 2 x 2 x 2 x 3 x 3
printPrimeFactor(1288); // 2 x 2 x 2 x 7 x 23




/*
run:

2
2
31


2
2
2
2
2
3
3


2
2
2
7
23

*/

 

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Answer 2

function getPrimeFactors(n) {
    const factors = [];
    let divisor = 2;

    while (n >= 2) {
        if (n % divisor === 0) {
            factors.push(divisor);
            n /= divisor;
        } else {
            divisor++;
        }
    }

    return factors;
}

const n = 124;
           
console.log(getPrimeFactors(n)); // 2 x 2 x 31
console.log(getPrimeFactors(288)); // 2 x 2 x 2 x 2 x 2 x 3 x 3
console.log(getPrimeFactors(1288)); // 2 x 2 x 2 x 7 x 23

 
 
/*
run:
     
[ 2, 2, 31 ]
[ 2, 2, 2, 2, 2, 3, 3 ]
[ 2, 2, 2, 7, 23 ]
      
*/

 

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