⚡ optimize error handling in json module

test/json.nas

@@ -39,6 +39,36 @@ println(ss, "\n");
 println(json.parse(ss), "\n");
 println(libjson.parse(ss), "\n");
 
+var test_func = func(input_string) {
+    var result = libjson.parse(input_string);
+    var errno = libjson.get_error();
+    if (!size(errno)) {
+        println("\e[92;1msuccess\e[0m:");
+        println("  ", result);
+    } else {
+        println("\e[91;1merror\e[0m:");
+        foreach(var err; split("\n", errno)) {
+            println("  |-> ", err);
+        }
+        println("  +-> generated with error:");
+        println("      +-> ", result);
+    }
+}
+
+test_func("[[]]");
+test_func("{\"1\":1}");
+test_func("[[[}]]]");
+test_func("=-==_+_+_+");
+test_func("123");
+test_func(libjson.stringify({
+    a: 0,
+    b: nil,
+    c: "this is a string",
+    d: [{}, [[1, 2, 4, 8, 16]]]
+}));
+test_func("");
+println();
+
 var test_json = func(json) {
     var bar = process_bar.high_resolution_bar(30);
     var tmp = [