Moore's Voting Algorithm in JavaScript

Understanding the Algorithm's Magic

At its core, Moore's Voting Algorithm relies on a simple yet brilliant observation. if an element appears more than half the time, any other element must appear less than half the time. So, we can essentially "cancel out" non-majority elements while keeping track of the potential winner.

Here's how it works

  1. Initialization: We start with two variables: candidate (initially null) and count (set to 0).
  2. Iteration: We loop through each element in the data.
    • If the count is 0, we set the current element as the candidate and reset the count to 1.
    • If the current element matches the candidate, we increment the count.
    • Otherwise, we decrease the count.
  3. Verification: After the loop, if the count is greater than half the data size, the candidate is the majority element. Otherwise, no majority element exists.

Putting Theory into Practice

function findMajorityElement(data) {
  let candidate = null;
  let count = 0;

  for (const element of data) {
    if (count === 0) {
      candidate = element;
      count = 1;
    } else if (element === candidate) {
    } else {

  if (count > data.length / 2) {
    return candidate;
  } else {
    return "No majority element found";

Example in Action: Let's Find the Winner

Now, let's test our code with some sample data.

const votes = ["Alice", "Bob", "Alice", "Bob", "Bob", "Alice", "Charlie"];
const majorityElement = findMajorityElement(votes);

console.log("The majority winner is:", majorityElement); 

// Output: The majority winner is: Alice

Beyond the Basics

Moore's Voting Algorithm shines in its efficiency, but it has limitations.

  • It only works if a true majority element exists.
  • It can't find multiple majority elements if they exist.

For these cases, advanced extensions or other algorithms might be needed.


Moore's Voting Algorithm is a valuable tool for finding majority elements in data. Its efficient and elegant approach makes it a go-to solution for various scenarios. By understanding its core principles and implementing them in JavaScript, you've equipped yourself with a powerful technique for your coding endeavors.