Dates are being appended a .000Z

[jmechevarria]

We use this library where I work, to create a SOAP client and make requests to an API, and we receive an XML which is parsed into JSON using this library.

After updating from 0.45 to the latest version, we noticed a problem with the dates when compared as they are in the original XML, and in the resulting JSON.

Example: 2026-06-06T12:00:00 is turned into 2026-06-06T12:00:00.000Z.

We infer the library (or one of its dependencies) assumes the date to be UTC, and appends the .000Z, which completely breaks our logic since the date is actually local time in the context of our business.

We did some trial and error and identified the issue happening since version 1.1.1

Before we embark in our own post-processing solution to identify all affected fields and strip them of the .000Z. Is this expected behavior/by design? Arbitrarily appending a UTC offset to a date that has no offset info looks like a bug.

Thanks for looking into this.

[smokhov]

I don't think this is arbitrary when a timestamp has no timezone in it. I think this is the default behaviour of the Date() class; its internal structure uses UTC. This is why there is an example for a custom deserializer: https://github.com/vpulim/node-soap?tab=readme-ov-file#custom-deserializer

I will let @w666 to confirm.

[w666]

@jmechevarria

I am not sure what do you mean, sorry.

String like 2026-06-06T12:00:00.000Z is a valid ISO format.

To help you with the problem I need more details.

Could you please provide an example of the RAW XML payload your receive from the server and the javascript object you get after client processed it. WSDL would help too.

If you can't provide those then snippets with removed PII are also okay.

Also, could you check from what version it stopped working for you? There are quite many changes and versions between 0.45 and 1.1.1

What's your Node.js version?

Thanks.

[jmechevarria]

String like 2026-06-06T12:00:00.000Z is a valid ISO format.

It definitely is, but that's not the point. The issue is that the original string (in the XML response) does not contain .000Z, and the resulting string (in the JSON object) does. This effectively changes the meaning of the string (from potentially any offset to always UTC)

Could you please provide an example of the RAW XML payload your receive from the server and the javascript object you get after client processed it. WSDL would help too.

If you can't provide those then snippets with removed PII are also okay.

<Item>
  <STA>2026-03-10T18:25:00</STA>
  <STD>2026-03-10T13:25:00</STD>
  <ItemInfo>
    <AltSTA>2026-01-23T16:13:49.7494192</AltSTA>
    <AltSTD>2026-01-23T16:13:49.7494192</AltSTD>
  </ItemInfo>
</Item>

{
  "STA": "2026-03-10T18:25:00.000Z",
  "STD": "2026-03-10T13:25:00.000Z",
  "ItemInfo": {
    "AltSTA": "2026-01-23T16:13:49.749Z",
    "AltSTD": "2026-01-23T16:13:49.749Z",
  }
}

Also, could you check from what version it stopped working for you? There are quite many changes and versions between 0.45 and 1.1.1

Sorry it was not clear from the original post. The issue started on 1.1.1. We're currently locked on 1.1.0 to avoid the issue.

What's your Node.js version?

v22

Thanks.

[w666]

Hi @jmechevarria,

I created MR #1431 with a test, which, I think, replicates the behaviour you described in this issue. I executed this test against v1.1.1 and v1.1.0, it passed against both. Also, github pipeline executes tests against node 24, 22 and 20.

Could you please review the test if it actually replicates this. Could you run it on your machine?

Thanks.

[jmechevarria]

Sorry for the late reply.

This is what we did.

[w666]

Closing, feel free to create another issue or reopen if need any assistance with this.