A few martingale oriented inverse utility functions.

bet-utils.js

/**
 * Calculates the base bet from the current wager, multiplier, and streak.
 *
 * @param {number} wager - The current wager.
 * @param {number} multi - The multiplier.
 * @param {number} streak - The streak.
 * @returns {number} - The calculated base bet.
 */
const getBaseBetFromCurrent = (wager, multi, streak) => (wager / (multi ** streak));

/**
 * Calculates the bet size for a given streak based on the base bet, multiplier, and streak.
 *
 * @param {number} base - The base bet.
 * @param {number} multi - The multiplier.
 * @param {number} streak - The streak.
 * @returns {number} - The calculated bet size for the streak.
 */
const getBetSizeForStreak = (base, multi, streak) => (base * (multi ** streak));

/**
 * Calculates the total bet sum for a given streak based on the base bet, payout, multiplier, and streak.
 *
 * @param {number} base - The base bet.
 * @param {number} payout - The payout multiplier.
 * @param {number} multi - The multiplier.
 * @param {number} streak - The streak.
 * @returns {number} - The calculated total bet sum for the streak.
 */
const getBetSumForStreak = (base, payout, multi, streak) => (base * (multi ** streak) * payout) - (base * (payout - 1));

/**
 * Calculates the streak size from the base bet, current wager, and multiplier.
 *
 * @param {number} base - The base bet.
 * @param {number} wager - The current wager.
 * @param {number} multi - The multiplier.
 * @returns {number} - The calculated streak size.
 */
const getStreakSizeFromBet = (base, wager, multi) => (Math.log(wager / base) / Math.log(multi));

/**
 * Calculates the previous bet from the last bet and multiplier.
 *
 * @param {number} wager - The last wager.
 * @param {number} multi - The multiplier.
 * @returns {number} - The calculated previous bet.
 */
const getPrevBetFromLastBet = (wager, multi) => (wager / multi);

/**
 * Calculates the bet multiplier from the current wager and previous bet.
 *
 * @param {number} wager - The current wager.
 * @param {number} prev - The previous bet.
 * @returns {number} - The calculated bet multiplier.
 */
const getBetMultiFromPrevBet = (wager, prev) => (wager / prev);

/**
 * Calculates the optimal bet multiplier for a given payout.
 *
 * @param {number} payout - The payout multiplier.
 * @returns {number} - The calculated bet multiplier.
 */
const getBetMultiForPayout = (payout) => (payout / (payout - 1));

/**
 * Calculates the payout from the bet multiplier.
 *
 * @param {number} multi - The bet multiplier.
 * @returns {number} - The calculated payout.
 */
const getPayoutFromBetMulti = (multi) => (multi / (multi - 1));

examples.js

// Example usage for getBaseBetFromCurrent
// Returns the base bet for a wager of 100, multiplier of 2, and streak of 3.
const baseBet = getBaseBetFromCurrent(100, 2, 3); // 12.5

// Example usage for getBetSizeForStreak
// Returns the bet size for a base bet of 50, multiplier of 2, and streak of 4.
const betSize = getBetSizeForStreak(50, 2, 4); // 800

// Example usage for getBetSumForStreak
// Returns the total bet sum for a base bet of 25, payout of 3, multiplier of 2, and streak of 5.
const betSum = getBetSumForStreak(25, 3, 2, 5); // 2350

// Example usage for getStreakSizeFromBet
// Returns the streak size for a base bet of 20, current wager of 80, and multiplier of 2.
const streakSize = getStreakSizeFromBet(20, 80, 2); //2

// Example usage for getPrevBetFromLastBet
// Returns the previous bet for a last wager of 150 and multiplier of 2.
const prevBet = getPrevBetFromLastBet(150, 2); // 75

// Example usage for getBetMultiFromPrevBet
// Returns the bet multiplier for a current wager of 120 and previous bet of 60.
const betMulti = getBetMultiFromPrevBet(120, 60); // 2

// Example usage for getBetMultiForPayout
// Returns the bet multiplier for a payout of 2.5.
const payoutMulti = getBetMultiForPayout(2.5); // 1.66

// Example usage for getPayoutFromBetMulti
// Returns the payout for a bet multiplier of 1.8.
const payout = getPayoutFromBetMulti(1.8); // 2.25