This is a fork of sudoku library available here: https://github.com/apieceofbart/sudoku.js.

It was forked in order to make it more playable！

Sudoku.js

A Sudoku puzzle generator and solver JavaScript library.

Check out the Online DEMO to see it in action.

Implementation ideas borrowed from "Solving Every Sudoku Puzzle" by Peter Norvig, and a generator/solver by Michael Anderson.

Features

🧩 Generate, Solve and Show Candidates the Sudoku
  （Basic features in Sudoku.js）
🔥 Fill or mark in the blanks
🌟 Touch input, suitable for mobile terminals
🎨 Warnings after errors 
📦 Background music and mute
🎁 Simple html-js-css code, easy to read and modify

Usage

Browser

Just add a script with the sudoku.js file. This will create a global variable sudoku.

Node

npm install sudoku-umd --save

then

// CommonJs
const sudoku = require('sudoko-umd');

// ES6
import sudoku from 'sudoku-umd';

API

Puzzles are represented by a string of digits, 1-9, and '.' as spaces. Each character represents a square, e.g.,

"52...6.........7.13...........4..8..6......5...........418.........3..2...87....."

Represents the following board:

5 2 . | . . 6 | . . .   
. . . | . . . | 7 . 1   
3 . . | . . . | . . .   
------+-------+------
. . . | 4 . . | 8 . .   
6 . . | . . . | . 5 .   
. . . | . . . | . . .   
------+-------+------
. 4 1 | 8 . . | . . .   
. . . | . 3 . | . 2 .   
. . 8 | 7 . . | . . .

(See the included converstion functions to convert between string representations and grids, i.e., two-dimensional arrays.)

Generate a Sudoku puzzle

Generage a Sudoku puzzle of a particular difficulty, e.g,

>>> sudoku.generate("easy")
"672819345193..4862485..3197824137659761945283359...714.38..1426.174.6.38.463...71"

>>> sudoku.generate("medium")
"8.4.71.9.976.3....5.196....3.7495...692183...4.5726..92483591..169847...753612984"

>>> sudoku.generate("hard")
".17..69..356194.2..89..71.6.65...273872563419.43...685521......798..53..634...59."

Valid difficulties are as follows, and represent the number of given squares:

"easy":         62
"medium":       53
"hard":         44
"very-hard":    35
"insane":       26
"inhuman":      17

You may also enter a custom number of squares to give, e.g.,

>>> sudoku.generate(60)
"8941376521532687497269548...72.9158.538.4219..19.852..3874.69.52415793689658.34.."

The number of givens must be a number between 17 and 81 inclusive. If it's outside of that range, the number of givens will be set to the closest bound, e.g., 0 will be treated as 17, and 100 as 81.

By default, the puzzles should have unique solutions, unless you set unique to false, e.g.,

sudoku.generate("easy", false)

Note: Puzzle uniqueness is not yet implemented, so puzzles are not guaranteed to have unique solutions.

Solve a Sudoku puzzle

Solve a Sudoku puzzle given a Sudoku puzzle represented as a string, e.g.,

>>> sudoku.solve(".17..69..356194.2..89..71.6.65...273872563419.43...685521......798..53..634...59.");
"217386954356194728489257136165948273872563419943712685521439867798625341634871592"

Board string ↔ grid

Board string → grid:

>>> sudoku.board_string_to_grid("23.94.67.8..3259149..76.32.1.....7925.321.4864..68.5317..1....96598721433...9...7")
[
    ["2","3",".","9","4",".","6","7","."],
    ["8",".",".","3","2","5","9","1","4"],
    ["9",".",".","7","6",".","3","2","."],
    ["1",".",".",".",".",".","7","9","2"],
    ["5",".","3","2","1",".","4","8","6"],
    ["4",".",".","6","8",".","5","3","1"],
    ["7",".",".","1",".",".",".",".","9"],
    ["6","5","9","8","7","2","1","4","3"],
    ["3",".",".",".","9",".",".",".","7"]
]

Board grid → string:

>>> sudoku.board_grid_to_string([
    ["2","3",".","9","4",".","6","7","."],
    ["8",".",".","3","2","5","9","1","4"],
    ["9",".",".","7","6",".","3","2","."],
    ["1",".",".",".",".",".","7","9","2"],
    ["5",".","3","2","1",".","4","8","6"],
    ["4",".",".","6","8",".","5","3","1"],
    ["7",".",".","1",".",".",".",".","9"],
    ["6","5","9","8","7","2","1","4","3"],
    ["3",".",".",".","9",".",".",".","7"]
])
"23.94.67.8..3259149..76.32.1.....7925.321.4864..68.5317..1....96598721433...9...7"

Get candidates

Get a grid of squares and their candidate values, propagating constraints, i.e., candidates restrict their peer candidates.

>>> sudoku.get_candidates("4.25..389....4.265..523.147..1652.7.6..1945322543876915....3.1....4..9.....8....3")
[
    ["4",     "167",    "2",    "5",  "167",  "16",   "3",   "8",  "9"  ],
    ["13789", "13789",  "3789", "79", "4",    "189",  "2",   "6",  "5"  ],
    ["89",    "689",    "5",    "2",  "3",    "689",  "1",   "4",  "7"  ],
    ["389",   "389",    "1",    "6",  "5",    "2",    "48",  "7",  "48" ],
    ["6",     "78",     "78",   "1",  "9",    "4",    "5",   "3",  "2"  ],
    ["2",     "5",      "4",    "3",  "8",    "7",    "6",   "9",  "1"  ],
    ["5",     "246789", "6789", "79", "267",  "3",    "478", "1",  "468"],
    ["1378",  "123678", "3678", "4",  "1267", "156",  "9",   "25", "68" ],
    ["179",   "124679", "679",  "8",  "1267", "1569", "47",  "25", "3"  ]
]

Print a board to the console

>>> sudoku.print_board(".17..69..356194.2..89..71.6.65...273872563419.43...685521......798..53..634...59.");
. 1 7   . . 6   9 . .   
3 5 6   1 9 4   . 2 .   
. 8 9   . . 7   1 . 6   

. 6 5   . . .   2 7 3   
8 7 2   5 6 3   4 1 9   
. 4 3   . . .   6 8 5   

5 2 1   . . .   . . .   
7 9 8   . . 5   3 . .   
6 3 4   . . .   5 9 .  

References:

• "Solving Every Sudoku Puzzle" by Peter Norvig
• Sudoku generator/solver for Mac OS X by Michael Anderson
• 95 Sudoku Puzzles
• Andrew Stuart's online Sudoku Solver