Add a script for checking for a winner

packages/game/src/js/connect4-winner.js

@@ -0,0 +1,69 @@
+let testBoard = [
+    ["_", "_", "_", "_", "_", "_", "_"],
+    ["_", "_", "_", "_", "_", "_", "_"],
+    ["_", "_", "_", "_", "r", "_", "_"],
+    ["_", "_", "_", "r", "r", "b", "b"],
+    ["_", "_", "r", "b", "r", "r", "b"],
+    ["b", "b", "b", "r", "r", "b", "b"]
+];
+
+/**
+ * Checks whether the specified {@link player `player`} is a winner according to the specified {@link board `board`}.
+ *
+ * @param {string} player
+ * The player to check for.
+ *
+ * @param {string[][]} board
+ * The board to check.
+ *
+ * @param {number} count
+ * The number of chips which need to be set in a row.
+ *
+ * @param {number} width
+ * The width of the board.
+ *
+ * @param {number} height
+ * The height of the board.
+ *
+ * @returns {boolean}
+ * A value indicating whether the specified {@link player `player`} did win.
+ */
+function connect4Winner(player, board, count = 4, width = 7, height = 6)
+{
+    for (let yOffset = 0; yOffset <= 1; yOffset++)
+    {
+        for (let xOffset = (-1 * yOffset) + (1 - yOffset); xOffset <= 1; xOffset++)
+        {
+            let lowerBound = Math.max(0, xOffset * (count - 1) * -1);
+            let upperBound = Math.min(width, width - (xOffset * (count - 1)));
+
+            for (let y = 0; y < (height - yOffset * (count - 1)); y++)
+            {
+                for (let x = lowerBound; x < upperBound; x++)
+                {
+                    /**
+                     * @type {string[]}
+                     */
+                    let tokens = [];
+
+                    for (let index = 0; index < count; index++)
+                    {
+                        tokens.push(board[y + index * yOffset][x + index * xOffset]);
+                    }
+
+                    if (tokens.every((token) => token === player))
+                    {
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+
+    return false;
+}
+
+module.exports = { connect4Winner };
+
+console.log(connect4Winner("r", testBoard));
+console.log(connect4Winner("b", testBoard));