n-digit-token/lib/library/calculateMax.js

Cryptographically secure pseudo-random token of n digits

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.calculateMax = void 0;
/**
 * Calculate largest possible value that avoids modulo bias.
 * @param {number} byteSize
 * @param {number} length
 * @return {bigint} max
 */
const calculateMax = ({ byteSize, length, }) => {
    const maxDecimal = BigInt(2n ** (BigInt(byteSize) * 8n) - 1n);
    return maxDecimal - (maxDecimal % 10n ** BigInt(length)) - 1n;
};
exports.calculateMax = calculateMax;