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0.1.2 • Public • Published

Available game parameters

There are many possible configuration. We are implementing Standard and Custom options so that you can easily combine flags to create games according with your skill/needs.

Standard variations

  • number of decks, default is 1
  • standOnSoft17, turn On/Off the "Soft 17" rule, default true
  • double, ability to double after deal, default any
    • none not allowed
    • any any allowed
    • 9or10
    • 9or10or11
    • 9thru15
  • split, On/Off the possibility to split after deal, default true
  • doubleAfterSplit, On/Off the possibility to double after split (split and double must be "on"), default true
  • surrender, on/off the ability to surrender after deal, default true
  • insurance, on/off the ability of ensuring a hand, default true


If you are using npm, to get the last version:

  • yarn add blackjack-engine
  • npm install blackjack-engine

Quick Start

Once obtained the library just require Game and actions.

const blackjack = require('blackjack-engine')
const actions = blackjack.actions
const Game = blackjack.Game

At this point you can initialize a new game by calling the Game constructor.

Creating a new game

const game = new Game()

In this cases, no state is passed to the constructor:

  1. the default state is loaded into game
  2. game is ready to dispatch actions to alter the state

Getting current state

At any moment we can require the current state of the game by calling the getState().


The content of the state and its schema depends on the stage of the game. In this case we initialized the game without any precedent state, so we will receive something like this:

For the moment the only thing we should note is that the field stage tells us "game is ready".

Dispatching actions

The only way to mutate the state of the game is to dispatch actions. Some actions are required by the "user", some other actions are dispatched by the engine to "complete" the game.

NOTE: In a real game, players and dealer are allowed to "do actions". The engine will "impersonate the dealer" at some point, depending on the last action and the state.

// stage is "ready"

// call an action to mutate the state

// stage has changed

Project Structure

Based on Marco Casula's project.


see the /src/actions.js

Engine exposes actions, once invoked, the state of the game is changed. The following list represent the actions that can be dispatched by from the public API.

  • bet
  • insurance
  • double
  • split
  • hit
  • stand
  • surrender

And, those are actions that are internally called in determinate stages by the engine itself.

  • deal-cards
  • showdown
  • dealerHit
  • invalid


See the /src/game.ts

The stage represent a moment in the game. The stage is directly related with the action allowed in that particular moment.

Current available stages for players are:

  • ready
  • insurance
  • players-turn
  • showdown
  • dealer-turn
  • done


The game logic is implemented into /src/engine.ts. There is a specific design limitation currently in the code.

NOTE: If you are interested in the random components, check out the shuffle() function.


Run tests by calling yarn test or npm test

Jest will care about the following tasks:

  • create a new game
  • initialize it by injecting ♠10 ♦1 ♥5 ♣6 ♠11 ♦10 at the and of the deck
  • run the desired restore, deal, split, insurance and finally stand
  • return the current state
  • compare if stage is 'done' at the end

If you specify the finalWin the test will compare the final winning.

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  • nugaon