Prime factor array of a Number in JavaScript

We are required to write a JavaScript function that takes in a number and returns an array of all the prime numbers that exactly divide the input number.

For example, if the input number is 105.

Then the output should be −

const output = [3, 5, 7];

Example

The code for this will be −

const num = 105;
const isPrime = (n) => {
   for(let i = 2; i <= n/2; i++){
      if(n % i === 0){
         return false;
      }
   };
   return true;
};
const findPrimeFactors = num => {
   const res = num % 2 === 0 ? [2] : [];
   let start = 3;
   while(start <= num){
      if(num % start === 0){
         if(isPrime(start)){
            res.push(start);
         };
      };
      start++;
   };
   return res;
};
console.log(findPrimeFactors(18));

Output

The output in the console −

[3, 5, 7]

AmitDiwan

Updated on 15-Oct-2020 09:30:04

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