JavaScript: Find all distinct prime factors of a given integer

JavaScript Basic: Exercise-132 with Solution

Write a JavaScript program to find all distinct prime factors of a given integer

Visual Presentation:

Sample Solution:

JavaScript Code:

// Function to find prime factors of a number
function prime_factors(num) {
  // Function to check if a number is prime
  function is_prime(num) {
    for (let i = 2; i <= Math.sqrt(num); i++) {
      if (num % i === 0) return false; // If the number is divisible by any number other than 1 and itself, it's not a prime
    }
    return true; // Return true if the number is prime
  }

  const result = []; // Initialize an empty array to store prime factors
  
  // Loop through numbers from 2 to 'num'
  for (let i = 2; i <= num; i++) {
    // While 'i' is a prime factor and divides 'num' evenly
    while (is_prime(i) && num % i === 0) {
      if (!result.includes(i)) result.push(i); // Add 'i' to the result array if it's not already present
      num /= i; // Divide 'num' by 'i'
    }
  }
  
  return result; // Return the array containing prime factors
}

// Test cases
console.log(prime_factors(100)); // Output: [2, 5]
console.log(prime_factors(101)); // Output: [101]
console.log(prime_factors(103)); // Output: [103]
console.log(prime_factors(104)); // Output: [2, 13]
console.log(prime_factors(105)); // Output: [3, 5, 7] 

Output:

[2,5]
[101]
[103]
[2,13]
[3,5,7]

Live Demo:

See the Pen javascript-basic-exercise-132 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

function prime_factors(num) {
  function is_prime(num) {
    for (let i = 2; i <= Math.sqrt(num); i++)
    {
      if (num % i === 0) return false;
    }
    return true;
  }
  const result = [];
  for (let i = 2; i <= num; i++)
  {
    while (is_prime(i) && num % i === 0) 
    {
      if (!result.includes(i)) result.push(i);
      num /= i;
    }
  }
  return result;
}
console.log(prime_factors(100));
console.log(prime_factors(101));
console.log(prime_factors(103));
console.log(prime_factors(104));
console.log(prime_factors(105));

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