A robust and adaptable Glicko-2 rating system library implemented in TypeScript. This library provides an accurate and dynamic method for tracking player performance by incorporating not only their rating but also the uncertainty (rating deviation) and consistency (volatility) of their play. Designed for online Chess game platforms.
Glicko-2 builds on the traditional Elo and Glicko systems by introducing two key concepts:
- Rating Deviation (RD): Quantifies the uncertainty in a player’s rating. Frequent play or recent games lead to lower RD, meaning more confidence in the rating.
- Volatility (σ): Measures the expected fluctuation in a player’s performance. Low volatility indicates stable performance, while high volatility suggests erratic results. This parameter allows the system to quickly adapt to changes in a player's form.
These features combine to offer a dynamic and statistically sound method to assess a player's true skill level—even when game frequency or consistency varies.
- Dynamic Rating Updates: Adjust ratings based on actual performance vs. expected outcomes.
- Integrated Uncertainty: Uses RD to measure confidence in the rating.
- Performance Volatility: Captures consistency with a volatility parameter that adjusts based on game results.
- Asynchronous Updates: Easily integrate with systems that require asynchronous operations.
Download the library from Github:
git clone https://github.com/singhDevs/glicko2-ts.gitImport the key functions, interfaces, and enums from the library:
import { updateRatings, PlayerRating, ResultType } from 'glicko2-ts';Use the updateRatings function to compute new ratings after a game between two players. The function requires:
whitePlayer: The current rating for the white side.blackPlayer: The current rating for the black side.result: Outcome of the game, represented as a ResultType enum.currentTime: A Date object for when the game was played, useful for RD adjustments. Example
const whitePlayer: PlayerRating = {
rating: 1500,
rd: 200,
volatility: 0.06,
lastGameTime: new Date('2025-03-01')
};
const blackPlayer: PlayerRating = {
rating: 1550,
rd: 180,
volatility: 0.05,
lastGameTime: new Date('2025-03-02')
};
async function processGame() {
const result = ResultType.DRAW; // or ResultType.WHITE / ResultType.BLACK
const currentTime = new Date();
const { newRatingWhite, newRatingBlack } = await updateRatings(
whitePlayer,
blackPlayer,
result,
currentTime
);
console.log('Updated White Rating:', newRatingWhite);
console.log('Updated Black Rating:', newRatingBlack);
}
processGame();Asynchronously computes and returns the new ratings for two players after a game.
async function updateRatings(
whitePlayer: PlayerRating,
blackPlayer: PlayerRating,
result: ResultType,
currentTime: Date
): Promise<{ newRatingWhite: PlayerRating; newRatingBlack: PlayerRating }>Parameters
whitePlayer(PlayerRating): The rating details for the white player.blackPlayer(PlayerRating): The rating details for the black player.result(ResultType): The outcome of the game (ResultType.WHITE, ResultType.BLACK, ResultType.DRAW)currentTime(Date): The timestamp of the game, used for adjusting RD.
Returns: A promise resolving to an object containing the updated ratings for both the players.
Represents a player's rating information:
export interface PlayerRating {
rating: number; // Current rating
rd: number; // Rating deviation (uncertainty)
volatility: number; // Volatility (rate of rating change)
lastGameTime: Date; // Time of last game for RD adjustment
};Defines possible game outcomes:
export enum ResultType {
WHITE, // White wins
BLACK, // Black wins
DRAW // Draw
}Glicko-2 Paper by Professor Mark E. Glickman: Glicko-2 paper
This project is licensed under the MIT license. See the LICENSE file for more info.