diff --git a/binding/javascript/tests/ip.test.js b/binding/javascript/tests/ip.test.js
index 481b13c..2e78433 100644
--- a/binding/javascript/tests/ip.test.js
+++ b/binding/javascript/tests/ip.test.js
@@ -10,7 +10,7 @@ import * as util from '../util.js';
 test('parse ip address', () => {
     let ip_list = [
         "1.0.0.0", "58.251.30.115", "192.168.1.100", "126.255.32.255", "219.xx.xx.11", 
-        "::", "::1", "fffe::", "2c0f:fff0::", "2c0f:fff0::1", 
+        "::", "::1", "fffe::", "2c0f:fff0::", "2c0f:fff0::1", "2a02:26f7:c409:4001::",
         "2fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "240e:982:e617:ffff:ffff:ffff:ffff:ffff", "::xx:ffff"
     ];
 
@@ -26,6 +26,7 @@ test('parse ip address', () => {
         let to_Str = ipBytes == null ? '0' : util.ipToString(ipBytes, true);
         let toByte = ipBytes == null ? '0' : util.ipBytesString(ipBytes);
         console.log(`parseIP(${ipString}): {Bytes: ${toByte}, String: ${to_Str}}`);
+        expect(ipString).toBe(to_Str);
     });
 });
 
diff --git a/binding/javascript/util.js b/binding/javascript/util.js
index d388715..4fb7c1a 100644
--- a/binding/javascript/util.js
+++ b/binding/javascript/util.js
@@ -196,7 +196,7 @@ function _ipv6_to_string(v6Bytes, compress) {
         _.push(''); // empty for double colon
 
         // make sure there is an empty tail
-        if (i == ps.length && _.length == 2) {
+        if (i == ps.length && _.length < ps.length) {
             _.push('');
         }
     }
@@ -375,4 +375,7 @@ export function loadContentFromFile(dbPath) {
     const content = loadContent(fd);
     fs.close(fd, function(){});
     return content;
-}
\ No newline at end of file
+}
+
+const ipBytes = parseIP("2a02:26f7:c409:4001::");
+console.log(ipToString(ipBytes));
\ No newline at end of file