@studimax/elo

Implementation of Elo rating system.

Installation

npm install @studimax/elo
# or
yarn add @studimax/elo

Usage

Calculate calculatePerformance

/**
* Calculates the probability to win based on the rating of the opponent.
* @param Ra Elo rating of hero A.
* @param Rb Elo rating of hero B.
*/
calculatePerformance(Ra: number, Rb: number): {Ea: number; Eb: number};

import Elo from '@studimax/elo';

const elo = new Elo();

/** Caclculate performance **/
const {Ea, Eb} = elo.calculatePerformance(1613, 1609);
// Ea: 0.506
// Eb: 0.494

Calculate Rating

/**
* Calculates the expected score of a hero based on the rating of the other hero.
* @param Ra Elo rating of hero A.
* @param Rb Elo rating of hero B.
* @param S Expected score of hero A. (0 <= S <= 1)
*/
calculateRating(Ra: number, Rb: number, S = 1): {Rb: number; Ra: number};

const elo = new Elo({kFactor: 20});
const {Ra, Rb} = elo.calculateRating(1800, 2005, 1); // 1 = win
// Ra: ~1815
// Rb: ~1990

const elo = new Elo({kFactor: 20});
const {Ra, Rb} = elo.calculateRating(1800, 2005, 0.5); // 0.5 = draw
// Ra: ~1805
// Rb: ~2000

const elo = new Elo({kFactor: 20});
const {Ra, Rb} = elo.calculateRating(1800, 2005, 0); // 0 = loss
// Ra: ~1795
// Rb: ~2010