Number of Wins

Number of Wins is a TypeScript library implementing win-counting tiebreaks for chess tournaments, following the FIDE Tiebreak Regulations (sections 7.1–7.4 and 7.6–7.8). Zero runtime dependencies.

Installation

npm install @echecs/number-of-wins

Quick Start

import { numberOfWins } from '@echecs/number-of-wins';
import type { Game, GameKind } from '@echecs/number-of-wins';

// games[n] = round n+1; Game has no `round` field
const games: Game[][] = [
  [{ black: 'B', result: 1, white: 'A' }], // round 1
  [{ black: 'C', result: 0.5, white: 'A' }], // round 2
  [{ black: 'A', result: 0, white: 'D' }], // round 3
  // kind distinguishes bye types for roundsElectedToPlay
  [{ black: 'A', kind: 'half-bye', result: 0.5, white: 'A' }], // round 4
];

const wins = numberOfWins('A', games);
// Returns 1 (one win including forfeit wins, byes are not wins here)

API

All functions accept (player: string, games: Game[][]) and return number. Round is determined by array position: games[0] = round 1, games[1] = round 2, etc. The Game type has no round field. The optional kind?: GameKind field on Game classifies unplayed rounds; values: 'forfeit-loss', 'forfeit-win', 'full-bye', 'half-bye', 'pairing-bye', 'zero-bye'. Bye games use the same player for both white and black.

numberOfWins(player, games)

FIDE section 7.1 — Total number of wins. Counts all games where player scored 1 point, including forfeit wins (bye rounds that award a full point).

import { numberOfWins, tiebreak } from '@echecs/number-of-wins';
// tiebreak is an alias for numberOfWins

gamesWon(player, games)

FIDE section 7.2 — Wins in played games only. Like numberOfWins but excludes bye rounds — only counts wins from over-the-board games.

import { gamesWon, tiebreak } from '@echecs/number-of-wins/games-won';

gamesPlayedWithBlack(player, games)

FIDE section 7.3 — Number of games played with the black pieces. Byes have no colour assignment and are excluded.

import { gamesPlayedWithBlack, tiebreak } from '@echecs/number-of-wins/black';

gamesWonWithBlack(player, games)

FIDE section 7.4 — Number of wins with the black pieces. Byes are excluded.

import {
  gamesWonWithBlack,
  tiebreak,
} from '@echecs/number-of-wins/won-with-black';

roundsElectedToPlay(player, games)

FIDE section 7.6 — Number of rounds the player chose to participate in. Returns the total number of games minus bye rounds.

import { roundsElectedToPlay, tiebreak } from '@echecs/number-of-wins/elected';

standardPoints(player, games)

FIDE section 7.8 — Points from standard (classical) time-control games. Counts only over-the-board results — wins score 1, draws score 0.5, losses score 0. Byes are excluded.

import { standardPoints, tiebreak } from '@echecs/number-of-wins/standard';

Subpath Exports

Each function is available as a standalone subpath export. Every subpath also exports a tiebreak alias for the primary function, plus the shared types.

Subpath	Function	Alias
@echecs/number-of-wins	numberOfWins	tiebreak
@echecs/number-of-wins/black	gamesPlayedWithBlack	tiebreak
@echecs/number-of-wins/elected	roundsElectedToPlay	tiebreak
@echecs/number-of-wins/games-won	gamesWon	tiebreak
@echecs/number-of-wins/standard	standardPoints	tiebreak
@echecs/number-of-wins/won-with-black	gamesWonWithBlack	tiebreak

Types

All subpath exports re-export the shared types:

import type { Game, GameKind, Player, Result } from '@echecs/number-of-wins';

Type	Description
Game	{ white: string; black: string; result: Result; kind?: GameKind }
GameKind	'forfeit-loss' | 'forfeit-win' | 'full-bye' | 'half-bye' | 'pairing-bye' | 'zero-bye'
Player	{ id: string }
Result	0 | 0.5 | 1

Contributing

Contributions are welcome. Please open an issue at github.com/echecsjs/number-of-wins/issues.