[njs] Fixed Error() constructor with no arguments.

[Dmitry Volyntsev]

details:   https://hg.nginx.org/njs/rev/88ff9dfa847e
branches:  
changeset: 1103:88ff9dfa847e
user:      hongzhidao <hongzhidao at gmail.com>
date:      Sun Aug 04 03:59:42 2019 -0400
description:
Fixed Error() constructor with no arguments.

diffstat:

 src/njs_error.c          |  10 +++-------
 src/njs_value.h          |   4 ++++
 src/test/njs_unit_test.c |   5 +++++
 3 files changed, 12 insertions(+), 7 deletions(-)

diffs (50 lines):

diff -r a07dc8b56fd3 -r 88ff9dfa847e src/njs_error.c
--- a/src/njs_error.c	Mon Aug 05 17:36:09 2019 +0300
+++ b/src/njs_error.c	Sun Aug 04 03:59:42 2019 -0400
@@ -133,14 +133,10 @@ njs_error_create(njs_vm_t *vm, njs_value
     njs_object_t       *error;
     const njs_value_t  *value;
 
-    if (nargs == 1) {
-        value = &njs_string_empty;
+    value = njs_arg(args, nargs, 1);
 
-    } else {
-        value = &args[1];
-    }
-
-    error = njs_error_alloc(vm, type, NULL, value);
+    error = njs_error_alloc(vm, type, NULL,
+                            njs_is_defined(value) ? value : NULL);
     if (njs_slow_path(error == NULL)) {
         return NJS_ERROR;
     }
diff -r a07dc8b56fd3 -r 88ff9dfa847e src/njs_value.h
--- a/src/njs_value.h	Mon Aug 05 17:36:09 2019 +0300
+++ b/src/njs_value.h	Sun Aug 04 03:59:42 2019 -0400
@@ -425,6 +425,10 @@ typedef struct {
     ((value)->type == NJS_UNDEFINED)
 
 
+#define njs_is_defined(value)                                                 \
+    ((value)->type != NJS_UNDEFINED)
+
+
 #define njs_is_null_or_undefined(value)                                       \
     ((value)->type <= NJS_UNDEFINED)
 
diff -r a07dc8b56fd3 -r 88ff9dfa847e src/test/njs_unit_test.c
--- a/src/test/njs_unit_test.c	Mon Aug 05 17:36:09 2019 +0300
+++ b/src/test/njs_unit_test.c	Sun Aug 04 03:59:42 2019 -0400
@@ -7865,6 +7865,11 @@ static njs_unit_test_t  njs_test[] =
     { njs_str("Error().__proto__.__proto__ == Object.prototype"),
       njs_str("true") },
 
+    { njs_str("Error.prototype.message = 'm';"
+              "Error.prototype.name = 'n';"
+              "new Error()"),
+      njs_str("n: m") },
+
     { njs_str("EvalError('e')"),
       njs_str("EvalError: e") },