locutus/esm/python/statistics/multimode.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

export function multimode(data) {
    //      discuss at: https://locutus.io/python/statistics/multimode/
    // parity verified: Python 3.12
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Returns all most-common values in first-seen order.
    //       example 1: multimode([1, 1, 2, 2, 3])
    //       returns 1: [1, 2]
    //       example 2: multimode(['a', 'b', 'a', 'b'])
    //       returns 2: ['a', 'b']
    //       example 3: multimode([])
    //       returns 3: []
    const values = assertStatisticsArray(data, 'multimode');
    const counts = new Map();
    const order = [];
    for (const value of values) {
        if (!counts.has(value)) {
            order.push(value);
        }
        counts.set(value, (counts.get(value) ?? 0) + 1);
    }
    let highestCount = 0;
    for (const count of counts.values()) {
        highestCount = Math.max(highestCount, count);
    }
    if (highestCount === 0) {
        return [];
    }
    return order.filter((value) => counts.get(value) === highestCount);
}
function assertStatisticsArray(data, functionName) {
    if (!Array.isArray(data)) {
        throw new TypeError(`${functionName}() data must be an array`);
    }
    return data;
}