Exes.js

A small library for managing Tic-Tac-Toe like games.

• Exes.js
• Installation
  • CJS
  • ESM
• Usage
  • Board
    • Basics
    • Create a New Board
    • Making a Move
    • Undoing a Move
    • Load
  • Search
• Example
  • Unbeatable Tic Tac Toe Computer

Installation

npm i exesjs

CJS

const { Board, search } = require('exesjs');

ESM

import { Board, search } from 'exesjs';

Usage

There are two main components to this library.

Board

Basics

The board manages things like which player's turn it is, placing a move, checking if the game is over, etc.

Board.internal is the internal representation of the game board. It is a one-dimensional array of numbers.

• -1 Represents an empty space.
• 0 Represents a space occupied by 'O.'
• 1 Represents a space occupied by 'X.'

Create a New Board

You can create a board by specifying a width, height, winLength, and turn.

const b = new Board({ width: 3, height: 3, winLength: 3, turn: 1 });
// Or leave the options blank to get a tic tac toe board.
const b = new Board();

Making a Move

Make moves on the board by calling board.move() It accepts two methods of moving.

Standard Move

A standard move can be made by simply passing a number — the position you want to play — to board.move.

const board = new Board();
board.move(4);
/*
-1 -1 -1
-1  1 -1
-1 -1 -1
*/

You can also specify a verbose move.

const board = new Board();
board.move({
  row: 2,
  col: 2,
});
/*
-1 -1 -1
-1  1 -1
-1 -1 -1
*/

You do not need to manually change board.turn, as it does so automatically.

Undoing a Move

You can undo a move by simply passing in the position you want to remove. Once again, the turn is automatically adjusted.

const board = new Board();
board.move(4);
/*
-1 -1 -1
-1  1 -1
-1 -1 -1
*/
board.undo(4);
/*
-1 -1 -1
-1 -1 -1
-1 -1 -1
*/

Load

You can load an array of moves into the board. Note: these moves must not be verbose.

const board = new Board();
board.load([4, 0, 8]);
/*
 0 -1 -1
-1  1 -1
-1 -1  1
*/

Search

You can have the computer pick a move by using the search function.

You must provide the search depth. But use caution, with great boards comes great search time.

const board = new Board();
board.load([4, 0, 8]);
/*
 0 -1 -1
-1  1 -1
-1 -1  1
*/
const bestMove = search(board, 4);

Example

Unbeatable Tic Tac Toe Computer

import { Board, search } from 'exesjs';
import readlineSync from 'readline-sync';

const board = new Board();

while (!board.isOver) {
  const move = search(board, 9);
  board.move(move);
  if (board.isOver) break;

  board.print();

  console.log('Your move: ');
  const input = readlineSync.question();

  board.move(parseInt(input));
}

board.print();
console.log(board.winner + ' wins!');