FizzBuzz Function

Goal: create a function fizzBuzz() that returns an array of 100 elements: multiples of 3 are replaced with “Fizz”, multiples of 5 with “Buzz”, and multiples of both 3 and 5 with “FizzBuzz”.

💡 Solution hint

Check for multiples of 15 first, then 3 and 5.
Build the result array and return it.

👀 Solution #1 (classic)

/**
 * FizzBuzz function - a classic divisibility test problem.
 * Returns an array where numbers divisible by 3 are replaced with "Fizz",
 * divisible by 5 with "Buzz", and divisible by both 3 and 5 (i.e., 15) with "FizzBuzz".
 * @returns {Array} Result array following FizzBuzz rules
 */
function fizzBuzz() {
  // Initialize array to store results
  const result = [];
  
  // Iterate through numbers 1 to 100 inclusive
  for (let i = 1; i <= 100; i++) {
    // Check divisibility by 15 first (to prevent
    // triggering separate 3 or 5 conditions)
    if (i % 15 === 0) {
      result.push('FizzBuzz');  // Divisible by both 3 and 5
    } 
    // If not divisible by 15, check for 3
    else if (i % 3 === 0) {
      result.push('Fizz');  // Divisible only by 3
    } 
    // If not divisible by 15 or 3, check for 5
    else if (i % 5 === 0) {
      result.push('Buzz');  // Divisible only by 5
    } 
    // If none of the above conditions are met
    else {
      result.push(i);  // Add the number itself
    }
  }
  
  // Return the populated results array
  return result;
}

Why this way:

Clear and readable.
Easy to extend or change conditions.
Time complexity O(n).

👀 Solution #2 (string concatenation)

function fizzBuzz() {
  const result = [];
  for (let i = 1; i <= 100; i++) {
    let str = '';
    if (i % 3 === 0) str += 'Fizz';
    if (i % 5 === 0) str += 'Buzz';
    result.push(str || i);
  }
  return result;
}

Why this way:

No duplicate checks.
Easy to scale for more divisors (e.g., 7 → ‘Bazz’).
Also O(n).

👀 Solution #3 (Array.from + map)

function fizzBuzz() {
  return Array.from({ length: 100 }, (_, idx) => {
    const i = idx + 1;
    let str = '';
    if (i % 3 === 0) str += 'Fizz';
    if (i % 5 === 0) str += 'Buzz';
    return str || i;
  });
}

Why this way:

Functional style and compactness.
No external mutable state.
Explicit mapping of index to value.

Task description

Write a function fizzBuzz that returns an array of length 100 with replacements:

Numbers divisible by 3 are replaced with “Fizz”
Numbers divisible by 5 are replaced with “Buzz”
Numbers divisible by both 3 and 5 are replaced with “FizzBuzz”

Examples

fizzBuzz()[2]; // "Fizz" (number 3)
fizzBuzz()[4]; // "Buzz" (number 5)
fizzBuzz()[14]; // "FizzBuzz" (number 15)

Requirements

The function must be named fizzBuzz
Do not print to console, return the array instead
Work for the range 1–100

Task description

Examples

Requirements

FizzBuzz Function

Task description

Examples

Requirements

🧑‍💻 It's not a bug! It's a feature!