simple-roundrobin/dist/index.js

A simple round-robin tournament scheduler

"use strict";
const createMatch = (home, away, randomizeHome = true, roundNumber) => {
    const match = randomizeHome && Math.random() < 0.5
        ? { home: away, away: home }
        : { home, away };
    return roundNumber ? { ...match, roundNumber } : match;
};
const rotateTeams = (teams) => {
    const newTeams = [...teams];
    const lastTeam = newTeams.pop();
    if (lastTeam) {
        newTeams.splice(1, 0, lastTeam);
    }
    return newTeams;
};
const reverseSchedule = (rounds) => rounds.map(round => round.map(match => ({
    home: match.away,
    away: match.home,
    roundNumber: match.roundNumber
})));
const scheduleGenerator = (legs, initialRounds) => {
    const additionalLegs = legs / 2;
    const reverseInitialRounds = reverseSchedule(initialRounds);
    const initial = [...initialRounds, ...reverseInitialRounds];
    return Array.from({ length: additionalLegs }, () => initial).flat();
};
const validateTeamNames = (teams) => {
    const seen = new Set();
    teams.forEach(team => {
        if (typeof team !== 'string' || team.trim() === '') {
            throw new Error(`Invalid team name: ${team}`);
        }
        if (seen.has(team)) {
            throw new Error(`Duplicate team name: ${team}`);
        }
        seen.add(team);
    });
};
const validateInput = (input) => {
    const { clubs, legs = 1 } = input;
    if (!Array.isArray(clubs)) {
        throw new Error("Clubs must be an array!");
    }
    validateTeamNames(clubs);
    if ((legs % 2 !== 0 && legs > 1) || legs < 1) {
        throw new Error('Legs value must be "1" or an even number.');
    }
    if (clubs.length === 0) {
        throw new Error("Clubs array cannot be empty.");
    }
    if (clubs.length % 2 !== 0) {
        throw new Error("Number of clubs must be even.");
    }
};
const generateRoundRobin = (input) => {
    const { clubs, legs = 1, randomizeHome = true } = input;
    validateInput(input);
    let teamsArray = [...clubs];
    const initialRounds = [];
    for (let i = 0; i < teamsArray.length - 1; i++) {
        const currentRound = [];
        for (let j = 0; j < teamsArray.length / 2; j++) {
            const teamOne = teamsArray[j];
            const teamTwo = teamsArray[teamsArray.length - 1 - j];
            currentRound.push(createMatch(teamOne, teamTwo, randomizeHome, i + 1));
        }
        initialRounds.push(currentRound);
        teamsArray = rotateTeams(teamsArray);
    }
    return legs === 1 ? initialRounds : scheduleGenerator(legs, initialRounds);
};
module.exports = generateRoundRobin;