[njs] Added signed zero support in njs.dump().

[Dmitry Volyntsev]

details:   https://hg.nginx.org/njs/rev/892680a2eae0
branches:  
changeset: 1015:892680a2eae0
user:      Artem S. Povalyukhin <artem.povaluhin at gmail.com>
date:      Tue Jun 25 00:06:12 2019 +0300
description:
Added signed zero support in njs.dump().

This closes #184 issue on Github.

diffstat:

 njs/njs_json.c           |  18 ++++++++++++++++++
 njs/test/njs_unit_test.c |   9 +++++++++
 2 files changed, 27 insertions(+), 0 deletions(-)

diffs (54 lines):

diff -r 56dee6c2ad95 -r 892680a2eae0 njs/njs_json.c
--- a/njs/njs_json.c	Sat Jun 22 23:35:52 2019 +0300
+++ b/njs/njs_json.c	Tue Jun 25 00:06:12 2019 +0300
@@ -2166,6 +2166,14 @@ njs_dump_value(njs_json_stringify_t *str
     case NJS_OBJECT_NUMBER:
         value = &value->data.u.object_value->value;
 
+        if (nxt_slow_path(value->data.u.number == 0.0
+                          && signbit(value->data.u.number)))
+        {
+
+            njs_dump("[Number: -0]");
+            break;
+        }
+
         ret = njs_number_to_string(stringify->vm, &str_val, value);
         if (nxt_slow_path(ret != NXT_OK)) {
             return NXT_ERROR;
@@ -2273,6 +2281,16 @@ njs_dump_value(njs_json_stringify_t *str
         return njs_json_buf_append(stringify, "]}", 2);
 
     case NJS_NUMBER:
+        if (nxt_slow_path(value->data.u.number == 0.0
+                          && signbit(value->data.u.number)))
+        {
+
+            njs_dump("-0");
+            break;
+        }
+
+        /* Fall through. */
+
     case NJS_REGEXP:
     case NJS_DATE:
     case NJS_OBJECT_ERROR:
diff -r 56dee6c2ad95 -r 892680a2eae0 njs/test/njs_unit_test.c
--- a/njs/test/njs_unit_test.c	Sat Jun 22 23:35:52 2019 +0300
+++ b/njs/test/njs_unit_test.c	Tue Jun 25 00:06:12 2019 +0300
@@ -12470,6 +12470,15 @@ static njs_unit_test_t  njs_test[] =
     { nxt_string("njs.dump(njs) == `{version:'${njs.version}'}`"),
       nxt_string("true") },
 
+    { nxt_string("njs.dump(-0)"),
+      nxt_string("-0") },
+
+    { nxt_string("njs.dump(Object(-0))"),
+      nxt_string("[Number: -0]") },
+
+    { nxt_string("njs.dump([0, -0])"),
+      nxt_string("[0,-0]") },
+
     /* Built-in methods name. */
 
     { nxt_string(