pinewood-derby-scheduler

A lane assignment scheduler for pinewood derby races. Generates fair race schedules that optimize for lane diversity, opponent variety, and fast race setup.

Live demo: https://pinewood.tomlee.space

Installation

npm install pinewood-derby-scheduler

Usage

import { schedule } from 'pinewood-derby-scheduler';

// Define your racers (can be any shape)
const racers = [
  { id: 1, name: 'Lightning' },
  { id: 2, name: 'Thunder' },
  { id: 3, name: 'Rocket' },
  { id: 4, name: 'Blaze' },
  { id: 5, name: 'Storm' },
];

// Generate a schedule
const raceSchedule = schedule(racers, {
  numLanes: 4,      // 4-lane track
  heatsPerRacer: 3, // each car races 3 times
});

// raceSchedule is a 2D array: [heat][lane]
raceSchedule.forEach((heat, i) => {
  console.log(`Heat ${i + 1}:`, heat.map(r => r?.name ?? '(empty)'));
});

Scheduling Criteria

The scheduler optimizes for three criteria, which you can prioritize in any order:

| Criterion | Description | |-----------|-------------| | 'lanes' | Lane diversity — Each racer uses different lanes across their heats | | 'opponents' | Opponent diversity — Each racer faces different opponents | | 'turnover' | Turnover — Minimize cars appearing in consecutive heats (faster race setup) |

Setting Priorities

Pass an array to prioritize to control the relative importance of each criterion. The first item has highest priority:

// Prioritize fast race setup, then opponent variety, then lane diversity
const raceSchedule = schedule(racers, {
  numLanes: 4,
  heatsPerRacer: 4,
  prioritize: ['turnover', 'opponents', 'lanes'],
});

// Prioritize lane diversity (default behavior)
const raceSchedule = schedule(racers, {
  numLanes: 4,
  heatsPerRacer: 4,
  prioritize: ['lanes', 'turnover', 'opponents'],
});

// Prioritize opponent variety above all else
const raceSchedule = schedule(racers, {
  numLanes: 4,
  heatsPerRacer: 4,
  prioritize: ['opponents', 'lanes', 'turnover'],
});

All three criteria are always considered; the priority order controls their relative weights (first = 1000, second = 100, third = 10).

Backward Compatibility

The old single-string format still works:

// These are equivalent:
prioritize: 'lanes'
prioritize: ['lanes', 'turnover', 'opponents']

// These are equivalent:
prioritize: 'opponents'
prioritize: ['opponents', 'turnover', 'lanes']

API

schedule<T>(racers: T[], options: ScheduleOptions): Schedule<T>

Generates a race schedule.

Parameters:

• racers — Array of racer objects (any shape)
• options.numLanes — Number of lanes on the track
• options.heatsPerRacer — How many heats each racer participates in
• options.prioritize — Priority order for scheduling criteria
  • Single criterion: 'lanes' | 'opponents' (backward compatible)
  • Array of criteria: ['lanes', 'turnover', 'opponents'] (any order)
  • Default: ['lanes', 'turnover', 'opponents']

Returns: A 2D array where result[heatIndex][laneIndex] is a racer or null (empty lane).

Types

type ScheduleCriterion = 'lanes' | 'opponents' | 'turnover';

interface ScheduleOptions {
  numLanes: number;
  heatsPerRacer: number;
  prioritize?: ScheduleCriterion | ScheduleCriterion[];
}

type Heat<T> = (T | null)[];
type Schedule<T> = Heat<T>[];

License

MIT