From c2eefda8f823958f3637079f41e783c4cbae9ffa Mon Sep 17 00:00:00 2001
From: Matt Basta <me@mattbasta.com>
Date: Thu, 6 Feb 2014 13:51:56 -0800
Subject: [PATCH] Add option to alphabetize object literals

---
 README.md                |  3 +++
 lib/compress.js          | 24 +++++++++++++++++++++++-
 test/compress/objects.js | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 test/compress/objects.js

diff --git a/README.md b/README.md
index 27d06cd6..6d15eea1 100644
--- a/README.md
+++ b/README.md
@@ -256,6 +256,9 @@ to set `true`; it's effectively a shortcut for `foo=true`).
 - `drop_console` -- default `false`.  Pass `true` to discard calls to
   `console.*` functions.
 
+- `alphabetize` -- default `false`.  Pass `true` to alphabetize keys in object
+  literals.
+
 ### The `unsafe` option
 
 It enables some transformations that *might* break code logic in certain
diff --git a/lib/compress.js b/lib/compress.js
index 005c606d..b434206b 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -72,6 +72,7 @@ function Compressor(options, false_by_default) {
         screw_ie8     : false,
         drop_console  : false,
         angular       : false,
+        alphabetize   : !false_by_default,
 
         warnings      : true,
         global_defs   : {}
@@ -2365,7 +2366,28 @@ merge(Compressor.prototype, {
         return self;
     };
     OPT(AST_Array, literals_in_boolean_context);
-    OPT(AST_Object, literals_in_boolean_context);
     OPT(AST_RegExp, literals_in_boolean_context);
+    OPT(AST_Object, function(self, compressor) {
+        if (compressor.option("alphabetize") && self.properties.length) {
+            var sortedProps = self.properties.sort(function(a, b) {
+                if (a.key < b.key) {
+                    return -1;
+                }
+                if (a.key > b.key) {
+                    return 1;
+                }
+                return 0;
+            });
+            for (var i = self.properties.length; i--;) {
+                if (self.properties[i] !== sortedProps[i]) {
+                    return make_node(AST_Object, self, {
+                        properties: sortedProps
+                    });
+                }
+            }
+        }
+
+        return literals_in_boolean_context(self, compressor);
+    });
 
 })();
diff --git a/test/compress/objects.js b/test/compress/objects.js
new file mode 100644
index 00000000..45eed8f4
--- /dev/null
+++ b/test/compress/objects.js
@@ -0,0 +1,35 @@
+alphabetize_disabled_by_default: {
+    options = {};
+    input: {
+        foo({
+            c: 1,
+            a: 2,
+            b: 3
+        });
+    }
+    expect: {
+        foo({
+            c: 1,
+            a: 2,
+            b: 3
+        });
+    }
+}
+
+alphabetize_orders_keys: {
+    options = { alphabetize: true };
+    input: {
+        foo({
+            c: 1,
+            a: 2,
+            b: 3
+        });
+    }
+    expect: {
+        foo({
+            a: 2,
+            b: 3,
+            c: 1
+        });
+    }
+}