everyutil/number/isKaprekar.js

A comprehensive library of lightweight, reusable utility functions for JavaScript and TypeScript, designed to streamline common programming tasks such as string manipulation, array processing, date handling, and more.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.isKaprekar = void 0;
/**
 * Checks if a number is a Kaprekar number.
 * For example, 45^2 = 2025, and 20 + 25 = 45.
 * @author @dailker
 * @param {number} n - The number to check.
 * @returns {boolean} True if n is a Kaprekar number, false otherwise.
 */
function isKaprekar(n) {
    if (n < 1)
        return false;
    const sq = (n * n).toString();
    for (let i = 1; i < sq.length; i++) {
        const left = parseInt(sq.slice(0, i), 10);
        const right = parseInt(sq.slice(i), 10);
        if (right && left + right === n)
            return true;
    }
    return n === 1;
}
exports.isKaprekar = isKaprekar;