diff --git a/include/ant.h b/include/ant.h
index 4fd7463..2e676da 100644
--- a/include/ant.h
+++ b/include/ant.h
@@ -54,6 +54,12 @@ jsval_t js_call(struct js *js, jsval_t func, jsval_t *args, int nargs);
 void js_set(struct js *, jsval_t, const char *, jsval_t);
 void js_merge_obj(struct js *, jsval_t dst, jsval_t src);
 
+jsval_t js_setprop(struct js *, jsval_t obj, jsval_t key, jsval_t val);
+void js_set_proto(struct js *, jsval_t obj, jsval_t proto);
+
+jsval_t js_get_proto(struct js *, jsval_t obj);
+jsval_t js_get_ctor_proto(struct js *, const char *name, size_t len);
+
 int js_type(jsval_t val);
 int js_getbool(jsval_t val);
 
diff --git a/meson.build b/meson.build
index deed231..cdb2d37 100644
--- a/meson.build
+++ b/meson.build
@@ -74,7 +74,7 @@ endif
 build_date = run_command('date', '+%Y-%m-%d', check: true).stdout().strip()
 
 version_conf = configuration_data()
-version_conf.set('ANT_VERSION', '0.0.7.34')
+version_conf.set('ANT_VERSION', '0.0.7.35')
 version_conf.set('ANT_GIT_HASH', git_hash)
 version_conf.set('ANT_BUILD_DATE', build_date)
 
diff --git a/src/ant.c b/src/ant.c
index 7144dab..92817d3 100644
--- a/src/ant.c
+++ b/src/ant.c
@@ -442,11 +442,18 @@ static jsval_t call_js_with_args(struct js *js, jsval_t func, jsval_t *args, int
 static jsval_t call_js_code_with_args(struct js *js, const char *fn, jsoff_t fnlen, jsval_t closure_scope, jsval_t *args, int nargs);
 static jsval_t start_async_in_coroutine(struct js *js, const char *code, size_t code_len, jsval_t closure_scope, jsval_t *args, int nargs);
 
+jsval_t js_get_proto(struct js *js, jsval_t obj);
+void js_set_proto(struct js *js, jsval_t obj, jsval_t proto);
+jsval_t js_setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v);
+static jsoff_t lkp_proto(struct js *js, jsval_t obj, const char *key, size_t len);
+jsval_t js_get_ctor_proto(struct js *js, const char *name, size_t len);
+static jsval_t get_prototype_for_type(struct js *js, uint8_t type);
+
+// Backward compat aliases (defined after implementations below)
 static jsval_t get_proto(struct js *js, jsval_t obj);
 static void set_proto(struct js *js, jsval_t obj, jsval_t proto);
-static jsoff_t lkp_proto(struct js *js, jsval_t obj, const char *key, size_t len);
 static jsval_t get_ctor_proto(struct js *js, const char *name, size_t len);
-static jsval_t get_prototype_for_type(struct js *js, uint8_t type);
+static jsval_t setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v);
 
 static void free_coroutine(coroutine_t *coro);
 static bool has_ready_coroutines(void);
@@ -1718,7 +1725,7 @@ static jsval_t mkprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v, bool is_
   return mkentity(js, (b & ~(3U | CONSTMASK)) | T_PROP, buf, sizeof(buf));
 }
 
-static jsval_t setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v) {
+jsval_t js_setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v) {
   jsoff_t koff = (jsoff_t) vdata(k);
   jsoff_t klen = offtolen(loadoff(js, koff));
   const char *key = (char *) &js->mem[koff + sizeof(jsoff_t)];
@@ -1736,6 +1743,10 @@ static jsval_t setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v) {
   return mkprop(js, obj, k, v, false);
 }
 
+static jsval_t setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v) {
+  return js_setprop(js, obj, k, v);
+}
+
 static inline jsoff_t esize(jsoff_t w) {
   jsoff_t cleaned = w & ~(GCMASK | CONSTMASK);
   switch (cleaned & 3U) {
@@ -2342,7 +2353,7 @@ static jsoff_t lkp(struct js *js, jsval_t obj, const char *buf, size_t len) {
   return lkp_inline(js, obj, buf, len);
 }
 
-static jsval_t get_proto(struct js *js, jsval_t obj) {
+jsval_t js_get_proto(struct js *js, jsval_t obj) {
   uint8_t t = vtype(obj);
 
   if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_mknull();
@@ -2360,7 +2371,11 @@ static jsval_t get_proto(struct js *js, jsval_t obj) {
   return (vt == T_OBJ || vt == T_ARR || vt == T_FUNC) ? val : js_mknull();
 }
 
-static void set_proto(struct js *js, jsval_t obj, jsval_t proto) {
+static jsval_t get_proto(struct js *js, jsval_t obj) {
+  return js_get_proto(js, obj);
+}
+
+void js_set_proto(struct js *js, jsval_t obj, jsval_t proto) {
   uint8_t t = vtype(obj);
   if (t != T_OBJ && t != T_ARR && t != T_FUNC) return;
   
@@ -2374,7 +2389,11 @@ static void set_proto(struct js *js, jsval_t obj, jsval_t proto) {
   }
 }
 
-static jsval_t get_ctor_proto(struct js *js, const char *name, size_t len) {
+static void set_proto(struct js *js, jsval_t obj, jsval_t proto) {
+  js_set_proto(js, obj, proto);
+}
+
+jsval_t js_get_ctor_proto(struct js *js, const char *name, size_t len) {
   jsoff_t ctor_off = lkp(js, js->scope, name, len);
   
   if (ctor_off == 0 && global_scope_stack) {
@@ -2400,6 +2419,10 @@ static jsval_t get_ctor_proto(struct js *js, const char *name, size_t len) {
   return resolveprop(js, mkval(T_PROP, proto_off));
 }
 
+static jsval_t get_ctor_proto(struct js *js, const char *name, size_t len) {
+  return js_get_ctor_proto(js, name, len);
+}
+
 static jsval_t get_prototype_for_type(struct js *js, uint8_t type) {
   switch (type) {
     case T_STR:     return get_ctor_proto(js, "String", 6);
@@ -10560,11 +10583,33 @@ jsval_t js_getthis(struct js *js) { return js->this_val; }
 jsval_t js_getcurrentfunc(struct js *js) { return js->current_func; }
 
 void js_set(struct js *js, jsval_t obj, const char *key, jsval_t val) {
+  size_t key_len = strlen(key);
+  
   if (vtype(obj) == T_OBJ) {
-    setprop(js, obj, js_mkstr(js, key, strlen(key)), val);
+    jsoff_t existing = lkp(js, obj, key, key_len);
+    if (existing > 0) {
+      if (is_const_prop(js, existing)) {
+        js_mkerr(js, "assignment to constant");
+        return;
+      }
+      saveval(js, existing + sizeof(jsoff_t) * 2, val);
+    } else {
+      jsval_t key_str = js_mkstr(js, key, key_len);
+      mkprop(js, obj, key_str, val, false);
+    }
   } else if (vtype(obj) == T_FUNC) {
     jsval_t func_obj = mkval(T_OBJ, vdata(obj));
-    setprop(js, func_obj, js_mkstr(js, key, strlen(key)), val);
+    jsoff_t existing = lkp(js, func_obj, key, key_len);
+    if (existing > 0) {
+      if (is_const_prop(js, existing)) {
+        js_mkerr(js, "assignment to constant");
+        return;
+      }
+      saveval(js, existing + sizeof(jsoff_t) * 2, val);
+    } else {
+      jsval_t key_str = js_mkstr(js, key, key_len);
+      mkprop(js, func_obj, key_str, val, false);
+    }
   }
 }
 
diff --git a/src/modules/json.c b/src/modules/json.c
index 522f291..c1eeeb2 100644
--- a/src/modules/json.c
+++ b/src/modules/json.c
@@ -200,9 +200,21 @@ jsval_t js_json_stringify(struct js *js, jsval_t *args, int nargs) {
 
 void init_json_module() {
   struct js *js = rt->js;
+  jsval_t glob = js_glob(js);
+  
+  jsval_t object_proto = js_get_ctor_proto(js, "Object", 6);
   jsval_t json_obj = js_mkobj(js);
   
-  js_set(js, js_glob(js), "JSON", json_obj);
-  js_set(js, json_obj, "parse", js_mkfun(js_json_parse));
-  js_set(js, json_obj, "stringify", js_mkfun(js_json_stringify));
+  if (js_type(object_proto) == JS_PRIV) {
+    js_set_proto(js, json_obj, object_proto);
+  }
+  
+  jsval_t parse_key = js_mkstr(js, "parse", 5);
+  jsval_t stringify_key = js_mkstr(js, "stringify", 9);
+  
+  js_setprop(js, json_obj, parse_key, js_mkfun(js_json_parse));
+  js_setprop(js, json_obj, stringify_key, js_mkfun(js_json_stringify));
+  
+  jsval_t json_key = js_mkstr(js, "JSON", 4);
+  js_setprop(js, glob, json_key, json_obj);
 }