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Packed card input (CardInput)

Most APIs that take hole cards, board cards, or dead cards accept CardInput:

  • string[] — canonical card strings (Ah, Th, 10c, …)
  • Uint8Array — one byte per card, each byte a deck id 0..51 (Node Buffer works as a byte view)

Deck id encoding​

index = rank * 4 + suit

Values
rank 0..122, 3, …, T, J, Q, K, A
suit 0..3c, d, h, s

Example: Ah → rank 12 (Ace), suit 2 (hearts) → 12 * 4 + 2 = **50**.

This matches the internal layout used by exact-equity enumeration in the native core.

Helpers (poker-calculations/encode)​

const encode = require('poker-calculations/encode');

const packed = encode.packCards(['Ah', 'Kh', 'Qh']);
const strings = encode.unpackCards(packed);
const id = encode.cardStringToDeckIndex('Ah'); // 50
const card = encode.deckIndexToCardString(50); // 'Ah'
const stateBytes = encode.packPokerState(gameState);
const stateObj = encode.unpackPokerState(stateBytes);

Pre-pack once in your app, then pass Uint8Array into hot paths (simulateHandOutcome, evaluateHandStrength, exactHuEquityVsRandomHand, decideAction state, etc.) to avoid per-card string parsing at the N-API boundary.

You can also obtain packed bytes directly from compact text:

const poker = require('poker-calculations');
const packed = poker.parseCompactCardList('AhKhQh', { outFormat: 'packed' });

TypeScript​

import type { CardInput, Card52 } from 'poker-calculations';

See also​

Card notation · Packed poker state