simple-statistics/src/mode.js

Simple Statistics

import modeSorted from "./mode_sorted.js";
import numericSort from "./numeric_sort.js";

/**
 * The [mode](https://en.wikipedia.org/wiki/Mode_%28statistics%29) is the number
 * that appears in a list the highest number of times.
 * There can be multiple modes in a list: in the event of a tie, this
 * algorithm will return the most recently seen mode.
 *
 * This is a [measure of central tendency](https://en.wikipedia.org/wiki/Central_tendency):
 * a method of finding a typical or central value of a set of numbers.
 *
 * This runs in `O(n log(n))` because it needs to sort the array internally
 * before running an `O(n)` search to find the mode.
 *
 * @param {Array<number>} x input
 * @returns {number} mode
 * @example
 * mode([0, 0, 1]); // => 0
 */
function mode(x) {
    // Sorting the array lets us iterate through it below and be sure
    // that every time we see a new number it's new and we'll never
    // see the same number twice
    return modeSorted(numericSort(x));
}

export default mode;