Complete rotateMatrix.js

rotateMatrix/rotateMatrix.js

@@ -43,5 +43,31 @@
  *  - Make your function accept a parameter for the direction of rotation (1 = clockwise, -1 = counterclockwise)
  */
 
-var rotateMatrix = function (matrix) {
-};
+var rotateMatrix = function (matrix, direction) {
+  direction = direction || 1;
+  if ( typeof direction !== 'number' ||  (direction !== 1 && direction !== -1) ) {
+    throw new Error('direction must be 1 for clockwise or -1 for counterclockwise');
+  }
+
+  var rows    = matrix.length;
+  var cols    = matrix[0].length;
+  var newRows = cols;
+  var newCols = rows;
+  var result  = [];
+  var i, j, k;
+
+  // give result matrix the correct number of rows
+  for (k = 0; k < cols; k += 1) {
+    result.push( [] );
+  }
+
+  for (i = 0; i < newRows; i += 1) {
+    for (j = 0; j < newCols; j += 1) {
+      result[i][j] = direction === 1 ?
+        matrix[newCols - j - 1][i] :
+        matrix[j][newRows - i - 1];
+    }
+  }
+
+  return result;
+};