Complete spiralTraversal.js using recursion

spiralTraversal/spiralTraversal.js

@@ -14,7 +14,61 @@
     returns [1, 2, 3, 6, 9, 8, 7, 4, 5]
  */
 
-var spiralTraversal = function(matrix){
+// Solved recursively for any 2-dimensional array (even if inner arrays are not the same length)
+var spiralTraversal = function (matrix) {
+  if (matrix.length === 0) return;
 
-  // TODO: Implement me!
-};
+  var result = [];
+  var currentRow, currentCol;
+
+  var goRight = function (matrix) {
+    var currentRow = 0; // always remove first row
+    while ( matrix[currentRow].length > 0 ) {
+      result.push ( matrix[currentRow].shift() );
+    }
+    matrix.shift();
+  };
+
+  var goDown = function (matrix) {
+    var currentRow = 0; // always start at first row and remove last column in that row
+    while ( matrix[currentRow] !== void 0 && matrix[currentRow][ matrix[currentRow].length - 1] !== void 0 ) {
+      result.push( matrix[currentRow].pop() );
+      currentRow += 1;
+    }
+  };
+
+  var goLeft = function (matrix) {
+    var currentRow = matrix.length - 1; // always remove last row
+    while ( matrix[currentRow].length > 0 ) {
+      result.push( matrix[currentRow].pop() );
+    }
+    matrix.pop();
+  };
+
+  var goUp = function (matrix) {
+    var currentRow = matrix.length - 1; // always start at last row and remove first column in that row
+    while ( matrix[currentRow] !== void 0 && matrix[currentRow][0] !== void 0 ) {
+      result.push( matrix[currentRow].shift() );
+      currentRow -= 1;
+    }
+  };
+
+  var move = function () {
+    goRight(matrix);
+    if (matrix.length === 0) return;
+
+    goDown(matrix);
+    if (matrix.length === 0) return;
+
+    goLeft(matrix);
+    if (matrix.length === 0) return;
+
+    goUp(matrix);
+    if (matrix.length === 0) return;
+
+    if ( matrix.length > 0 ) move();
+  };
+
+  move();
+  return result;
+};