linus/bingo.js

## bingo.js
// Takes a board generated by the bingo() function below, and returns
// a HTML table.
function boardToHTML(board) {
  return `
    <table>
      ${chunk(board, 3).map(card => `<tbody>
        ${card.map(row => `<tr>
          ${row.map(cell => `<td>
            ${cell ? cell.toString().padStart(2, '0') : ''}
          </td>`).join('')}
        </tr>`).join('')}
      </tbody>`).join('')}
    </table>
  `;

  // Utility to chunk an array into n size-sized sub-arrays
  function chunk(array, size) {
    const result = [];
    for (let i = 0, l = array.length; i < l; i += size) {
      result.push(array.slice(i, i + size));
    }
    return result;
  }
}

// Generate a UK-style Bingo board, with 18 rows and 9 columns, each
// row having exactly five (5) numbers, and column 1 having the numbers
// 1 through 9 (9 blanks), columns 2-8 having ten numbers each (8 blanks),
// and column 9 having the numbers 80 through 90 (7 blanks).
function bingo() {
  // This is our "blank" row, just to set out the pattern
  const row = [...new Array(5).fill(true), ...new Array(4).fill(false)];

  // We have all the numbers for each column here, randomly shuffled
  const cols = [
    range(1, 10),
    range(10, 20),
    range(20, 30),
    range(30, 40),
    range(40, 50),
    range(50, 60),
    range(60, 70),
    range(70, 80),
    range(80, 91),
  ].map(col => shuffle(col));

  // Create our board as an array of 18 rows, each containing a shuffled
  // transposition of the blank row above
  const board = Array.from({ length: 18 }, () => shuffle(row.slice(0)));

  // Switch two random cells in the same row, and check if the resulting
  // board is closer to our constraints. If not, switch them back and continue
  while (!valid(board)) {
    const row = random(0, 18);
    const col1 = random(0, 9);
    const col2 = random(0, 9);

    if (board[row][col1] === board[row][col2]) continue;

    const previous = Math.abs(board.map(row => row[col1]).filter(Boolean).length - cols[col1].length)
      + Math.abs(board.map(row => row[col2]).filter(Boolean).length - cols[col2].length);

    // try swapping
    const temp = board[row][col1];
    board[row][col1] = board[row][col2];
    board[row][col2] = temp;

    const score = Math.abs(board.map(row => row[col1]).filter(Boolean).length - cols[col1].length)
      + Math.abs(board.map(row => row[col2]).filter(Boolean).length - cols[col2].length);

    if (score > previous) {
      // it went bad, switch them back
      board[row][col2] = board[row][col1];
      board[row][col1] = temp;
    }
  }

  // Transform our board from the pattern (true if a number should be
  // in a cell, false otherwise) into a full board with numbers from
  // each column. Blanks are null.
  return board.map(row => row.map((cell, col) => cell ? cols[col].pop() : null));

  // Check if board is valid: Each row contains exactly five numbers,
  // column 1 contains exactly 9 numbers, columns 2-8 each contains exactly
  // 10 numbers, and column 9 contains exactly 11 numbers.
  function valid (board) {
    const transposed = transpose(board);
    return board.every(row => row.filter(Boolean).length === 5)
      && transposed.every((col, index) => col.filter(Boolean).length === cols[index].length);
  }

  // Get an array with numbers in range from and to
  function range (from, to) {
    return Array.from({ length: to - from }, (_, i) => i + from);
  }

  // Transpose two-dimensional array
  function transpose (array) {
    return array[0].map((_, i) => array.map((x) => x[i]));
  }

  // Shuffle array in place, while also returning the array
  function shuffle (array) {
    for (let i = array.length - 1; i > 0; i--) {
      const j = Math.floor(Math.random() * (i + 1));
      [array[i], array[j]] = [array[j], array[i]];
    }

    return array;
  }
}

## index.html
<!doctype html>
<head>
    <script src="bingo.js"></script>
    <style>
        table {
            border: 1px solid black;
            border-collapse: collapse;
        }
        tbody {
            border: 2px solid red;
        }
        tr {
            border: 1px solid black;
        }
        td {
            border: 1px solid black;
        }
    </style>
</head>
<body>
    <div id="board"></div>
    <button id="generate">Äh ge mig en ny bricka, va</button>
    <script>
       window.generate.onclick = () => {
           const originalText = window.generate.innerHTML;
           window.generate.innerHTML = "Räknar...";
           window.generate.disabled = true;
           window.requestAnimationFrame(() => {
             const bingoBoard = bingo();
             window.board.innerHTML = boardToHTML(bingoBoard);
             window.generate.disabled = false;
             window.generate.innerHTML = originalText;
           });
       }
    </script>
</body>
	// Takes a board generated by the bingo() function below, and returns
	// a HTML table.
	function boardToHTML(board) {
	return `
	<table>
	${chunk(board, 3).map(card => `<tbody>
	${card.map(row => `<tr>
	${row.map(cell => `<td>
	${cell ? cell.toString().padStart(2, '0') : ''}
	</td>`).join('')}
	</tr>`).join('')}
	</tbody>`).join('')}
	</table>
	`;

	// Utility to chunk an array into n size-sized sub-arrays
	function chunk(array, size) {
	const result = [];
	for (let i = 0, l = array.length; i < l; i += size) {
	result.push(array.slice(i, i + size));
	}
	return result;
	}
	}

	// Generate a UK-style Bingo board, with 18 rows and 9 columns, each
	// row having exactly five (5) numbers, and column 1 having the numbers
	// 1 through 9 (9 blanks), columns 2-8 having ten numbers each (8 blanks),
	// and column 9 having the numbers 80 through 90 (7 blanks).
	function bingo() {
	// This is our "blank" row, just to set out the pattern
	const row = [...new Array(5).fill(true), ...new Array(4).fill(false)];

	// We have all the numbers for each column here, randomly shuffled
	const cols = [
	range(1, 10),
	range(10, 20),
	range(20, 30),
	range(30, 40),
	range(40, 50),
	range(50, 60),
	range(60, 70),
	range(70, 80),
	range(80, 91),
	].map(col => shuffle(col));

	// Create our board as an array of 18 rows, each containing a shuffled
	// transposition of the blank row above
	const board = Array.from({ length: 18 }, () => shuffle(row.slice(0)));

	// Switch two random cells in the same row, and check if the resulting
	// board is closer to our constraints. If not, switch them back and continue
	while (!valid(board)) {
	const row = random(0, 18);
	const col1 = random(0, 9);
	const col2 = random(0, 9);

	if (board[row][col1] === board[row][col2]) continue;

	const previous = Math.abs(board.map(row => row[col1]).filter(Boolean).length - cols[col1].length)
	+ Math.abs(board.map(row => row[col2]).filter(Boolean).length - cols[col2].length);

	// try swapping
	const temp = board[row][col1];
	board[row][col1] = board[row][col2];
	board[row][col2] = temp;

	const score = Math.abs(board.map(row => row[col1]).filter(Boolean).length - cols[col1].length)
	+ Math.abs(board.map(row => row[col2]).filter(Boolean).length - cols[col2].length);

	if (score > previous) {
	// it went bad, switch them back
	board[row][col2] = board[row][col1];
	board[row][col1] = temp;
	}
	}

	// Transform our board from the pattern (true if a number should be
	// in a cell, false otherwise) into a full board with numbers from
	// each column. Blanks are null.
	return board.map(row => row.map((cell, col) => cell ? cols[col].pop() : null));

	// Check if board is valid: Each row contains exactly five numbers,
	// column 1 contains exactly 9 numbers, columns 2-8 each contains exactly
	// 10 numbers, and column 9 contains exactly 11 numbers.
	function valid (board) {
	const transposed = transpose(board);
	return board.every(row => row.filter(Boolean).length === 5)
	&& transposed.every((col, index) => col.filter(Boolean).length === cols[index].length);
	}

	// Get an array with numbers in range from and to
	function range (from, to) {
	return Array.from({ length: to - from }, (_, i) => i + from);
	}

	// Transpose two-dimensional array
	function transpose (array) {
	return array[0].map((_, i) => array.map((x) => x[i]));
	}

	// Shuffle array in place, while also returning the array
	function shuffle (array) {
	for (let i = array.length - 1; i > 0; i--) {
	const j = Math.floor(Math.random() * (i + 1));
	[array[i], array[j]] = [array[j], array[i]];
	}

	return array;
	}
	}
	<!doctype html>
	<head>
	<script src="bingo.js"></script>
	<style>
	table {
	border: 1px solid black;
	border-collapse: collapse;
	}
	tbody {
	border: 2px solid red;
	}
	tr {
	border: 1px solid black;
	}
	td {
	border: 1px solid black;
	}
	</style>
	</head>
	<body>
	<div id="board"></div>
	<button id="generate">Äh ge mig en ny bricka, va</button>
	<script>
	window.generate.onclick = () => {
	const originalText = window.generate.innerHTML;
	window.generate.innerHTML = "Räknar...";
	window.generate.disabled = true;
	window.requestAnimationFrame(() => {
	const bingoBoard = bingo();
	window.board.innerHTML = boardToHTML(bingoBoard);
	window.generate.disabled = false;
	window.generate.innerHTML = originalText;
	});
	}
	</script>
	</body>