From e093716ebedd9b092120f488ec8bf0d97f0c53d4 Mon Sep 17 00:00:00 2001
From: Jeff Williams <jeffrey.l.williams@gmail.com>
Date: Fri, 5 Sep 2014 15:12:57 -0700
Subject: [PATCH] handle sparse arrays correctly in nodeToString (#749)

---
 lib/jsdoc/src/astnode.js        | 7 ++++++-
 test/specs/jsdoc/src/astnode.js | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/jsdoc/src/astnode.js b/lib/jsdoc/src/astnode.js
index f82254bb..26782164 100644
--- a/lib/jsdoc/src/astnode.js
+++ b/lib/jsdoc/src/astnode.js
@@ -138,8 +138,13 @@ var nodeToString = exports.nodeToString = function(node) {
         case Syntax.ArrayExpression:
             tempObject = [];
             node.elements.forEach(function(el, i) {
+                // handle sparse arrays. use `null` to represent missing values, consistent with
+                // JSON.stringify([,]).
+                if (!el) {
+                    tempObject[i] = null;
+                }
                 // preserve literal values so that the JSON form shows the correct type
-                if (el.type === Syntax.Literal) {
+                else if (el.type === Syntax.Literal) {
                     tempObject[i] = el.value;
                 }
                 else {
diff --git a/test/specs/jsdoc/src/astnode.js b/test/specs/jsdoc/src/astnode.js
index 24ba2c82..6e1f35db 100644
--- a/test/specs/jsdoc/src/astnode.js
+++ b/test/specs/jsdoc/src/astnode.js
@@ -13,6 +13,7 @@ describe('jsdoc/src/astnode', function() {
     };
 
     // create the AST nodes we'll be testing
+    var arrayExpression = esprima.parse('[,]').body[0].expression;
     var assignmentExpression = esprima.parse('foo = 1;').body[0].expression;
     var binaryExpression = esprima.parse('foo & foo;').body[0].expression;
     var functionDeclaration1 = esprima.parse('function foo() {}').body[0];
@@ -793,6 +794,10 @@ describe('jsdoc/src/astnode', function() {
     });
 
     describe('nodeToString', function() {
+        it('should return `[null]` for the sparse array `[,]`', function() {
+            expect( astnode.nodeToString(arrayExpression) ).toBe('[null]');
+        });
+
         it('should return the variable name for assignment expressions', function() {
             expect( astnode.nodeToString(assignmentExpression) ).toBe('foo');
         });
@@ -848,7 +853,7 @@ describe('jsdoc/src/astnode', function() {
         });
 
         it('should return the variable name for variable declarators', function() {
-            expect ( astnode.nodeToString(variableDeclarator1) ).toBe('foo');
+            expect( astnode.nodeToString(variableDeclarator1) ).toBe('foo');
         });
 
         it('should return an empty string for all other nodes', function() {