Parse top-level floating comments

index.js

@@ -146,13 +146,17 @@ module.exports = function (indexes) {
         file: data.file
       };
 
-      if (path.parent.node) {
+      if (path.parent && path.parent.node) {
         comment.context.code = code.substring
           .apply(code, path.parent.node.range);
       }
     }
 
     types.visit(ast, {
+      visitProgram: makeVisitor(function (comment, node, path) {
+        addContext(comment, path);
+      }),
+
       visitMemberExpression: makeVisitor(function (comment, node, path) {
         inferName(comment, node.property.name);
         addContext(comment, path);

test/fixture/comment-only.output.json

@@ -1 +1,28 @@
-[]
+[
+  {
+    "description": "This function returns the number one.",
+    "tags": [
+      {
+        "title": "return",
+        "description": "numberone",
+        "type": {
+          "type": "NameExpression",
+          "name": "Number"
+        }
+      }
+    ],
+    "context": {
+      "loc": {
+        "start": {
+          "line": 5,
+          "column": 0
+        },
+        "end": {
+          "line": 5,
+          "column": 0
+        }
+      },
+      "file": "fixture/comment-only.input.js"
+    }
+  }
+]