locutus/python/statistics/median.js

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

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.median = median;
function median(data) {
    //      discuss at: https://locutus.io/python/statistics/median/
    // parity verified: Python 3.12
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Returns the middle data point, averaging the two middle numeric points for even-length input.
    //       example 1: median([1, 3, 5])
    //       returns 1: 3
    //       example 2: median([1, 2, 3, 4])
    //       returns 2: 2.5
    //       example 3: median(['b', 'a', 'c'])
    //       returns 3: 'b'
    const values = sortStatisticsValues(data, 'median');
    if (values.length === 0) {
        throw new Error('no median for empty data');
    }
    const middleIndex = Math.floor(values.length / 2);
    if (values.length % 2 === 1) {
        return values[middleIndex];
    }
    const left = values[middleIndex - 1];
    const right = values[middleIndex];
    if (typeof left === 'string' || typeof right === 'string') {
        throw new TypeError("unsupported operand type(s) for /: 'str' and 'int'");
    }
    return (toStatisticNumber(left, 'median') + toStatisticNumber(right, 'median')) / 2;
}
function sortStatisticsValues(data, functionName) {
    if (!Array.isArray(data)) {
        throw new TypeError(`${functionName}() data must be an array`);
    }
    if (data.length === 0) {
        return [];
    }
    const values = data;
    const firstKind = getStatisticsSortKind(values[0], functionName);
    for (let index = 1; index < values.length; index += 1) {
        if (getStatisticsSortKind(values[index], functionName) !== firstKind) {
            throw new TypeError(`${functionName}() requires data values that can be ordered together`);
        }
    }
    return [...values].sort((left, right) => compareStatisticsValues(left, right, firstKind));
}
function toStatisticNumber(value, functionName) {
    if (typeof value === 'number') {
        return value;
    }
    if (typeof value === 'boolean') {
        return value ? 1 : 0;
    }
    if (typeof value === 'bigint') {
        const numericValue = Number(value);
        if (!Number.isSafeInteger(numericValue)) {
            throw new RangeError(`${functionName}() bigint values must fit within JS safe integers`);
        }
        return numericValue;
    }
    throw new TypeError(`${functionName}() data must contain only real numbers`);
}
function getStatisticsSortKind(value, functionName) {
    if (typeof value === 'string') {
        return 'string';
    }
    if (typeof value === 'number' || typeof value === 'boolean' || typeof value === 'bigint') {
        return 'number';
    }
    throw new TypeError(`${functionName}() requires sortable scalar values`);
}
function compareStatisticsValues(left, right, kind) {
    if (kind === 'string') {
        return String(left).localeCompare(String(right));
    }
    return toNumericSortValue(left) - toNumericSortValue(right);
}
function toNumericSortValue(value) {
    return typeof value === 'boolean' ? (value ? 1 : 0) : Number(value);
}