Poker Hand Evaluator

This is the official repository of the npm module poker-evaluator.

This is a poker hand evaluator using the Two Plus Two algorithm and lookup table. The lookup table HandRanks.dat is included in the module.

Capable of evaluating 3, 5, 6 and 7 card hands. The highest hand possible in a 3 card hand is 3 of a kind (straights & flushes do not apply to 3 cards).

This can evaluate about 22MM hands per second on a quad-core 2.7GHz Macbook Pro. Run the speedtest.js file under /test to try it.

Installation

npm install poker-evaluator OR
yarn add poker-evaluator

Usage:

Call the public evalHand method with a single argument, an array of 3, 5, 6 or 7 cards as:

• Strings in the format 'Xy' where X = rank and y = suit. This is case insensitive so xy or XY (or any other combination) work fine too.
  • Ranks: A, 1, 2, 3, 4, 5, 6, 7, 8, 9, T, J, Q, K
  • Suits: c, d, h, s
• Numbers corresponding to the values in the deck (currently does not work for 3 card hands)

Call the public winningOddsForPlayer method to estimate the odds of winning a hand given your cards. This returns a single PlayerOdds record. Example usage:

winningOddsForPlayer(['ah','as'],[],5, 1000) // {'winRate':0.56,'splitRates':[{'rate':0.006, 'ways':2},...{'rate':...,'ways':n}]}
winningOddsForPlayer(['ah','as'],['2c','3c','4c','5c'],5, 1000) // {'winRate':0.03...}
winningOddsForPlayer(['ah','as'],[],2, 1000) // {'winRate':0.85,...}

Call the public winningHandsForTable method to get spectator odds for each players hand. This returns a TableOdds record. Example usage:

winningOddsForTable([['ah','as'],['kd','kh']], [], 2, 1000) // {'players':[{'winRate'...},...]}

This can be called with partial hands, such as:

winningOddsForTable([['ah','as'],['kd'],[]], [], 3, 1000)

See odds types for the structure of odds.

See src/constants/deck.const.ts for the full deck

Typescript:

import * as PokerEvaluator from 'poker-evaluator-ts';

PokerEvaluator.evalHand(['As', 'Ks', 'Qs', 'Js', 'Ts', '3c', '5h']);
//{ handType: 9,
//  handRank: 10,
//  value: 36874,
//  handName: 'straight flush' }

PokerEvaluator.evalHand(['As', 'Ac', 'Qs']);
//{ handType: 2,
//  handRank: 2761,
//  value: 10953,
//  handName: 'one pair' }

Importing in JavaScript:

const PokerEvaluator = require('poker-evaluator');

Passing numbers as arguments (values from deck.const.ts):

PokerEvaluator.evalHand([17, 22, 27, 32, 33]);
//{ handType: 5,
//  handRank: 6,
//  value: 20486,
//  handName: 'straight' }

The returned object is an EvaluatedHand (src/types/evaluated-hand.interface.ts). An explanation of its properties is as follows:

handType: number; // Index of the HAND_TYPES array  
handRank: number; // Rank within the handType  
value: number; // Overall value of this hand, the higher the better. USE THIS TO DETERMINE WINNER OF A HAND  
handName: HandName; // Human readable name of the hand

Contributing

To contribute create a pull request from your fork to this repository.

Contributors

David Chen - Wrote original poker-evaluator

Rory Mcgit - Made project typescript friendly

Aaron Segal - Added odds calculator