@tungstenstudio/outschart-generator

Darts outs/checkout chart generator with pre-computed lookups and a miss-aware recommendation engine.

Live Demo

Features

• Instant lookups — pre-computed double-out and single-out charts, zero computation
• Generation engine — brute-force enumerate all possible checkouts (82K double-out, 242K single-out)
• Miss-aware recommendations — scoring algorithm using physical dartboard layout, segment areas, and bust risk
• Notation presets — format charts for different regional conventions (british, american, or custom)
• Zero dependencies — pure TypeScript, works in Node.js and browsers

Install

npm install @tungstenstudio/outschart-generator

Quick Start

import { getCheckout, getCheckoutChart, getBogeyNumbers } from '@tungstenstudio/outschart-generator';

// Instant lookup
getCheckout(170, 'double');
// { darts: ['T20', 'T20', 'Bull'], numDarts: 3 }

getCheckout(40, 'double');
// { darts: ['D20'], numDarts: 1 }

// Full chart
const chart = getCheckoutChart('double');

// Bogey numbers (no checkout possible)
getBogeyNumbers('double');
// [159, 162, 163, 165, 166, 168, 169]

API

Lookup Functions (pre-computed, instant)

getCheckout(score, outMode?)

Returns the recommended checkout for a single score, or null if not checkable.

getCheckout(92, 'double')
// { darts: ['T20', 'D16'], numDarts: 2 }

getCheckoutChart(outMode?, range?)

Returns the full checkout chart, optionally filtered by score range.

getCheckoutChart('single', { min: 1, max: 60 })

getBogeyNumbers(outMode?)

Returns scores that cannot be finished in 3 darts.

isCheckable(score, outMode?)

Returns true if the score has a checkout in the pre-computed chart.

Generation Engine (computational)

generateAllCheckouts(options)

Brute-force enumerates ALL possible checkouts.

const result = generateAllCheckouts({ outMode: 'double' });
// result.totalOptions === 82047
// result.checkouts[170].options === [['T20', 'T20', 'Bull']]

generateRecommended(options)

Generates a miss-aware recommended chart using the scoring algorithm.

const result = generateRecommended({
  outMode: 'single',
  includeAlternates: true,
  altThreshold: 1.0,
  overrides: { 100: { darts: ['T20', '20', '20'] } },
});

Notation / Internationalization

formatDart(dart, notation)

Formats a single dart label using a notation preset or custom map.

import { formatDart, NOTATIONS } from '@tungstenstudio/outschart-generator';

formatDart('T20', NOTATIONS.british)  // 'T20'
formatDart('Bull', NOTATIONS.british) // 'DB'
formatDart('25', NOTATIONS.american)  // 'SB'
formatDart('20', NOTATIONS.explicit)  // 'S20'

formatCheckoutChart(chart, notation)

Formats an entire checkout chart. Accepts a preset name string or a NotationMap object.

import { getCheckoutChart, formatCheckoutChart } from '@tungstenstudio/outschart-generator';

const chart = getCheckoutChart('double');

// Use a built-in preset by name
const british = formatCheckoutChart(chart, 'british');
british[170].darts // ['T20', 'T20', 'DB']

// Use a fully custom notation
const custom = formatCheckoutChart(chart, {
  treble: 'Triple ',
  double: 'Double ',
  single: '',
  bull: 'Bullseye',
  outerBull: 'Outer Bull',
});
custom[170].darts // ['Triple 20', 'Triple 20', 'Bullseye']

NOTATIONS

Built-in notation presets:

| Preset | Treble | Double | Single | Bull | 25 | |--------|--------|--------|--------|------|------| | default | T20 | D20 | 20 | Bull | 25 | | british | T20 | D20 | S20 | DB | SB | | american | T20 | D20 | 20 | DB | SB | | explicit | T20 | D20 | S20 | Bull | 25 |

Utilities

parseTarget(str)

Parses dart notation into components.

parseTarget('D16') // { bed: 'double', number: 16, value: 32 }
parseTarget('T20') // { bed: 'treble', number: 20, value: 60 }
parseTarget('Bull') // { bed: 'Bull', number: null, value: 50 }

formatTarget(bed, number)

Inverse of parseTarget — formats a bed/number pair into label and value.

Types

• OutMode — 'double' | 'single'
• CheckoutEntry — { darts: string[]; numDarts: number; alternates?: string[][] }
• CheckoutChart — Record<number, CheckoutEntry>
• ParsedTarget — { bed: BedType; number: number | null; value: number }
• NotationMap — { treble: string; double: string; single: string; bull: string; outerBull: string }
• OutsChartError — Custom error class with semantic codes

Development

npm install
npm run test        # Run tests
npm run typecheck   # Type-check
npm run build       # Build ESM + CJS + DTS
npm run build:demo  # Build demo IIFE bundle
npm run dev         # Build demo and serve locally
npm run verify      # Run all checks

License

ISC