`msg.getContact()` throws “Data passed to getter must include an id property” on some `message_create` events

[faytecCD]

Is there an existing issue for this?

• I have searched the existing issues.

Is this a problem caused by your code, or is it specifically because of the library?

• I have double-checked my code carefully.

Describe the bug.

When handling the message_create event and calling msg.getContact(), execution sometimes fails inside the WhatsApp Web runtime with:

Expected Behavior

No Exception.

Steps to Reproduce the Bug or Issue

client.on('message_create', async (msg) => {
  try {
    const isGroupMsg = (await msg.getChat()).isGroup;
    const from = await msg.getContact(); // crashes intermittently here
    console.log({ isGroupMsg, from: from?.id?._serialized });
  } catch (err) {
    console.error('message_create handler error:', err);
  }
});

Note

• I mainly use this in group chats, which may be one of the reasons

• This issue also appears in other variant methods such as 'client.getContactById'

• This issue usually occurs after the service has been running for some time (once the error appears, sending or receiving messages with the bot’s own account will continuously fail, though messages sent by other members can still be received normally). It cannot be reproduced on the first run.

Restarting the service can temporarily resolve it, but not always.

WhatsApp Account Type

Standard

Browser Type

Google Chrome

Operation System Type

Linux

Phone OS Type

Android

WhatsApp-Web.js Version

"whatsapp-web.js": "github:pedroslopez/whatsapp-web.js#5438c2042b9b42370c0acef21e511c08bb462983"

WhatsApp Web Version

2.3000.1030467071

Node.js Version

v23.11.0

Authentication Strategy

LocalAuth

Additional Context

/home/www/msg-bot.example.com/node_modules/puppeteer-core/lib/cjs/puppeteer/common/ExecutionContext.js:229
        throw new Error('Evaluation failed: ' + (0, util_js_1.getExceptionMessage)(exceptionDetails));
              ^

Error: Evaluation failed: Error: Data passed to getter must include an id property (it's how we memoize) but got undefined
    at new Error (<anonymous>:6:31)
    at s (https://static.whatsapp.net/rsrc.php/v4/yu/r/4wLJsIo9jix.js:77:180)
    at v (https://static.whatsapp.net/rsrc.php/v4/y1/r/c7DeHfEEslf.js:557:4487)
    at Object.h [as getIsMe] (https://static.whatsapp.net/rsrc.php/v4/y1/r/c7DeHfEEslf.js:557:2443)
    at window.WWebJS.getContactModel (pptr://__puppeteer_evaluation_script__:640:48)
    at window.WWebJS.getContact (pptr://__puppeteer_evaluation_script__:666:30)
    at ExecutionContext._ExecutionContext_evaluate (/home/www/msg-bot.example.com/node_modules/puppeteer-core/lib/cjs/puppeteer/common/ExecutionContext.js:229:15)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async ExecutionContext.evaluate (/home/www/msg-bot.example.com/node_modules/puppeteer-core/lib/cjs/puppeteer/common/ExecutionContext.js:107:16)
    at async Client.getContactById (/home/www/msg-bot.example.com/node_modules/whatsapp-web.js/src/Client.js:1190:23)
    at async Client.<anonymous> (/home/www/msg-bot.example.com/index.js:154:22)

This appears to occur on certain message types/sources (e.g., system/broadcast/newsletter/status or self messages) where the underlying contact model does not have a valid id when getIsMe is evaluated.

Additional context 2

• The error occurs at index.js:154 on const from = await msg.getContact(); with code path: message_create → msg.getContact() → Client.getContactById → WA Web evaluation.

Package version

at Fixing msg.getContact and getContactById (#3978)

"whatsapp-web.js": "github:pedroslopez/whatsapp-web.js#5438c2042b9b42370c0acef21e511c08bb462983"

Thank you.

[RC047]

I think maybe the problem is when this function is executed, and with the same error.

When the contact data is obtained in the getContact function, it does not return the perfect object data, perhaps there is an error in your code related to this.

[jasonfish568]

But if you read again:

client.on('message_create', async (msg) => {
  try {
    const isGroupMsg = (await msg.getChat()).isGroup;
    const from = await msg.getContact(); // crashes intermittently here
    console.log({ isGroupMsg, from: from?.id?._serialized });
  } catch (err) {
    console.error('message_create handler error:', err);
  }
});

This is basically just client.on('message_create')'s callback.
The getIsMe() is called in Whatapp-web.js, not in our code.

We understand that the msg object may not be perfect but it is still a bug within Whatsapp-web.js I believe.

[faytecCD]

@RC047 Yes, ChatGPT also told me that this is the reason:

getIsMe expects an object with an id property, but the object passed in does not have an id attribute.

But I am still not entirely sure where the issue actually occurs. At first, I used code like the following to fetch the contact, and it would also cause the same error:

const from = await client.getContactById(isGroupMsg ? (msg.author ?? msg.from) : msg.from);

So I went back to the documentation and switched to using msg.getContact(), but it behaves the same way. In group chats, after running for a while, this error starts happening again.

And this error only appears for my own account.

To clarify, I use whatsapp-web.js to log in with Account A, and I also have Account A logged in on my phone. Sometimes, I send group messages on my phone using Account A. After whatsapp-web.js has been running for a while, this issue occurs. As mentioned earlier, it may not happen at first, but after some time, it does.

When the error occurs, I can still properly process (receive) messages sent by other group members. However, messages I send myself—either from the phone or through the whatsapp-web.js API—cannot be processed.

Why do I need to do this?

To avoid this becoming an X-Y problem, I’ll clarify the goal: I want to get the sender’s @c.us ID, not @lid or @g.us.

The reason is that @c.us uniquely identifies a specific contact, which I need to store in my database. This ensures that messages from the same person across different chats can still be linked to a single contact.

So here, I use (await msg.getContact()).id._serialized to obtain the sender’s contact ID.

---

I plan to investigate this issue again to see if something went wrong somewhere.

[faytecCD]

@RC047

I re-reviewed the implementation of msg.getContact.

getContact() {
    return this.client.getContactById(this.author || this.from);
}

It looks quite similar to how I was calling it before.
Then I continued to check the implementation of client.getContactById, which actually calls the Web WhatsApp API inside the browser environment:

• getContactById

async getContactById(contactId) {
    let contact = await this.pupPage.evaluate(contactId => {
        return window.WWebJS.getContact(contactId);
    }, contactId);

    return ContactFactory.create(this, contact);
} 

• WWebJS.getContact

window.WWebJS.getContact = async contactId => {
    const wid = window.Store.WidFactory.createWid(contactId);
    let contact = await window.Store.Contact.find(wid);
    if (contact.id._serialized.endsWith('@lid')) {
        contact.id = contact.phoneNumber;
    }
    const bizProfile = await window.Store.BusinessProfile.fetchBizProfile(wid);
    bizProfile.profileOptions && (contact.businessProfile = bizProfile);
    return window.WWebJS.getContactModel(contact);
};

From what I found, if contactId is undefined, null, or an invalid ID, the step window.Store.WidFactory.createWid(contactId) will throw an exception.

For null/undefined/empty: wid error: invalid wid,
so the problem is not here (this method seems to only validate the ID format).

When the ID does not exist (changing the digits before @, e.g. await window.WWebJS.getContact('456712341114@lid')), createWid does not fail.

Note: For invalid IDs, I found that the contact returned from await window.Store.Contact.find sometimes has its id as undefined, and sometimes as an id object.

Case A: contact.id === undefined
Then if (contact.id._serialized.endsWith('@lid')) throws:
TypeError: Cannot read properties of undefined (reading 'serialized').

Case B: contact.id is a valid-looking object, and since it ends with @lid, it gets replaced by contact.phoneNumber and returns normally.

But if contact.phoneNumber is undefined, then in getContactModel during getIsMe, another error will be thrown:
Data passed to getter must include an id property (it's how we memoize) but got undefined.

I tested valid @lid contacts, and their IDs should end up as @c.us.

So, the root cause is that the contact object returned by window.Store.Contact.find(wid) may have id or phoneNumber missing.

This behavior happens with invalid contacts. However, assuming that we passed a valid contactId and the issue still happens occasionally, it suggests that the corresponding contact stored in WhatsApp Web may be incomplete (missing id or phoneNumber), leading to persistent errors.

Another thing worth mentioning: for invalid IDs, on the first call to getContact the code hangs at:
const bizProfile = await window.Store.BusinessProfile.fetchBizProfile(wid);
Perhaps valid IDs skip this and move forward properly.

So we may need to consider the case where contact.id ends with @lid and contact.phoneNumber is empty.

---

All of the above is my speculation, but I discovered a new issue:
Some incoming messages from group chats have an id in msg.author or msg.from like this:
456712341114:56@lid
meaning there is an extra colon and number after the numeric ID.
This seems to be the real root of the problem.

Can you explain what this :56 means? Thanks.

Maybe I should sanitize this ID?

---

• Example:

let fromId = String(msg.author || msg.from);
// sanitizeId, eg: 12345:67@lid => 12345@lid
if (fromId.includes(':') && fromId.endsWith('@lid') && fromId.match(/:\d+@lid$/)) {
    fromId = fromId.replace(/:\d+@lid$/, '@lid');
}
from = await client.getContactById(fromId);

[faytecCD]

After further log tracing, I confirmed that this issue is indeed caused by that reason. The logs show that the author field contains an abnormal value.

Here is the log output:

[2025-12-04 01:27:00] ERROR: ❌ [bot-01] Failed to get message sender information: xxxxxxxxxxxxx@lid
    msg_context: {
      "author": "154864650254076:21@lid",
      "from": "154864650254076@lid",
      "to": "1023114192666948@g.us",
      "timestamp": 1764811620,
      "id": "xxxxxxxxxxxxx@lid"
    }
/home/www/msg-bot.example.com/node_modules/puppeteer-core/lib/cjs/puppeteer/common/ExecutionContext.js:229
        throw new Error('Evaluation failed: ' + (0, util_js_1.getExceptionMessage)(exceptionDetails));
              ^

Error: Evaluation failed: Error: Data passed to getter must include an id property (it's how we memoize) but got undefined
    at new Error (<anonymous>:6:31)
    at s (https://static.whatsapp.net/rsrc.php/v4/y3/r/QZsume-GUVi.js:77:180)
    at v (https://static.whatsapp.net/rsrc.php/v4/yy/r/hI8nbjV5Mhx.js:557:4487)
    at Object.h [as getIsMe] (https://static.whatsapp.net/rsrc.php/v4/yy/r/hI8nbjV5Mhx.js:557:2443)
    at window.WWebJS.getContactModel (pptr://__puppeteer_evaluation_script__:640:48)
    at window.WWebJS.getContact (pptr://__puppeteer_evaluation_script__:666:30)
    at ExecutionContext._ExecutionContext_evaluate (/home/www/msg-bot.example.com/node_modules/puppeteer-core/lib/cjs/puppeteer/common/ExecutionContext.js:229:15)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async ExecutionContext.evaluate (/home/www/msg-bot.example.com/node_modules/puppeteer-core/lib/cjs/puppeteer/common/ExecutionContext.js:107:16)
    at async Client.getContactById (/home/www/msg-bot.example.com/node_modules/whatsapp-web.js/src/Client.js:1190:23)
    at async Client.<anonymous> (/home/www/msg-bot.example.com/index.js:156:20)

[N0N4M3BNS]

@faytecCD The solution you suggest now is cleaning in our code, right? I will try on my side to see if it works or not.

[faytecCD]

@N0N4M3BNS

Yes. I’ve stopped using msg.getContact() in my code and switched to the approach shown in the example above. After running it for a while, the issue has not appeared again.