From 1f97b7af05b49ef69bd6e9d54906d1b7583f42c4 Mon Sep 17 00:00:00 2001
From: dcodeIO <dcode@dcode.io>
Date: Thu, 23 Mar 2017 03:10:42 +0100
Subject: [PATCH] New: Constructors/.create always initialize proper mutable
 objects/arrays, see #700

---
 src/class.js     |  5 +----
 src/converter.js | 23 ++++++++++++++---------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/src/class.js b/src/class.js
index 51cbb31d0..5ef00b5b5 100644
--- a/src/class.js
+++ b/src/class.js
@@ -77,15 +77,12 @@ function Class(type, ctor) {
 Class.generate = function generate(type) { // eslint-disable-line no-unused-vars
     /* eslint-disable no-unexpected-multiline */
     var gen = util.codegen("p");
-    // see issue #700: the following would add explicitly initialized mutable object/array fields
-    // so that these aren't just inherited from the prototype. will break test cases.
-    /*
+    // explicitly initialize mutable object/array fields so that these aren't just inherited from the prototype
     for (var i = 0, field; i < type.fieldsArray.length; ++i)
         if ((field = type._fieldsArray[i]).map) gen
             ("this%s={}", util.safeProp(field.name));
         else if (field.repeated) gen
             ("this%s=[]", util.safeProp(field.name));
-    */
     return gen
     ("if(p){")
         ("for(var ks=Object.keys(p),i=0;i<ks.length;++i)")
diff --git a/src/converter.js b/src/converter.js
index 684781c0b..969f1bde0 100644
--- a/src/converter.js
+++ b/src/converter.js
@@ -229,7 +229,7 @@ converter.toObject = function toObject(mtype) {
 
     if (normalFields.length) { gen
     ("if(o.defaults){");
-        for (i = 0, field; i < normalFields.length; ++i) {
+        for (i = 0; i < normalFields.length; ++i) {
             var field = normalFields[i],
                 prop  = util.safeProp(field.name);
             if (field.resolvedType instanceof Enum) gen
@@ -247,25 +247,30 @@ converter.toObject = function toObject(mtype) {
         } gen
     ("}");
     }
-    for (i = 0, field; i < fields.length; ++i) {
+    for (i = 0; i < fields.length; ++i) {
         var field = fields[i],
-            prop  = util.safeProp(field.name); gen
-    ("if(m%s!==undefined&&m%s!==null&&m.hasOwnProperty(%j)){", prop, prop, field.name);
+            index = mtype._fieldsArray.indexOf(field),
+            prop  = util.safeProp(field.name);
         if (field.map) { gen
+    ("var ks2")
+    ("if(m%s&&(ks2=Object.keys(m%s)).length){", prop, prop)
         ("d%s={}", prop)
-        ("for(var ks2=Object.keys(m%s),j=0;j<ks2.length;++j){", prop);
-            genValuePartial_toObject(gen, field, /* sorted */ mtype._fieldsArray.indexOf(field), prop + "[ks2[j]]")
+        ("for(var j=0;j<ks2.length;++j){");
+            genValuePartial_toObject(gen, field, /* sorted */ index, prop + "[ks2[j]]")
         ("}");
         } else if (field.repeated) { gen
+    ("if(m%s&&m%s.length){", prop, prop)
         ("d%s=[]", prop)
         ("for(var j=0;j<m%s.length;++j){", prop);
-            genValuePartial_toObject(gen, field, /* sorted */ mtype._fieldsArray.indexOf(field), prop + "[j]")
+            genValuePartial_toObject(gen, field, /* sorted */ index, prop + "[j]")
         ("}");
-        } else
-        genValuePartial_toObject(gen, field, /* sorted */ mtype._fieldsArray.indexOf(field), prop);
+        } else { gen
+    ("if(m%s!==undefined&&m%s!==null&&m.hasOwnProperty(%j)){", prop, prop, field.name);
+        genValuePartial_toObject(gen, field, /* sorted */ index, prop);
         if (field.partOf) gen
         ("if(o.oneofs)")
             ("d%s=%j", util.safeProp(field.partOf.name), field.name);
+        }
         gen
     ("}");
     }