Table view breaks on multiple assymetrical columns

miguel-mconf · May 16, 2025, 4:05pm

Describe the problem/error/question

When handling with data with multiple columns, and the number of columns on each item is different, the last visible column on table view can show undefined when data actually exists.

In my example, there are two items with properties ranging from a - z and aa-ao, so 41 properties in total. The difference between them is that the 2nd item doesn’t have the “an” property, so it has only 40 properties. In this case the table view shows undefined on ao property in item 1, even though it has the ao property set with value ao.

This does not affect JSON visualization or the actual workflow, only the table visualization.

What is the error message (if any)?

First item is incorrect in table view (shows ao as undefined):

JSON view is correct:

Please share your workflow

EDIT: pinned the data so the bug is clearly visible.

Share the output returned by the last node

Full output (the output is correct, only the table visualization is incorrect):

[
  {
    "a": "a",
    "b": "b",
    "c": "c",
    "d": "d",
    "e": "e",
    "f": "f",
    "g": "g",
    "h": "h",
    "i": "i",
    "j": "j",
    "k": "k",
    "l": "l",
    "m": "m",
    "n": "n",
    "o": "o",
    "p": "p",
    "q": "q",
    "r": "r",
    "s": "s",
    "t": "t",
    "u": "u",
    "v": "v",
    "w": "w",
    "x": "x",
    "y": "y",
    "z": "z",
    "aa": "aa",
    "ab": "ab",
    "ac": "ac",
    "ad": "ad",
    "ae": "ae",
    "af": "af",
    "ag": "ag",
    "ah": "ah",
    "ai": "ai",
    "aj": "aj",
    "ak": "ak",
    "al": "al",
    "am": "am",
    "an": "an",
    "ao": "ao"
  },
  {
    "a": "a",
    "b": "b",
    "c": "c",
    "d": "d",
    "e": "e",
    "f": "f",
    "g": "g",
    "h": "h",
    "i": "i",
    "j": "j",
    "k": "k",
    "l": "l",
    "m": "m",
    "n": "n",
    "o": "o",
    "p": "p",
    "q": "q",
    "r": "r",
    "s": "s",
    "t": "t",
    "u": "u",
    "v": "v",
    "w": "w",
    "x": "x",
    "y": "y",
    "z": "z",
    "aa": "aa",
    "ab": "ab",
    "ac": "ac",
    "ad": "ad",
    "ae": "ae",
    "af": "af",
    "ag": "ag",
    "ah": "ah",
    "ai": "ai",
    "aj": "aj",
    "ak": "ak",
    "al": "al",
    "am": "am",
    "ao": "ao"
  }
]

Information on your n8n setup

n8n version: 1.85.4
Database (default: SQLite): SQLite
n8n EXECUTIONS_PROCESS setting (default: own, main): own
Running n8n via (Docker, npm, n8n cloud, desktop app): k8s
Operating system: ubuntu

mohamed3nan · May 16, 2025, 4:19pm

Hi @miguel-mconf

I believe this behavior is intended by design.

Please read the hint:

miguel-mconf · May 16, 2025, 5:06pm

Hey, thank you for your reply, but this is most certainly not the intended behavior.
I’m very familiar with the hidden columns mechanism, I’ve being using it for years now.
ao column shows value undefined, which is wrong, as it should show ao just like the line below…

mohamed3nan · May 16, 2025, 5:09pm

I mean it’s probably a UI/front-end issue…

Are there any issues with the actual workflow?

I don’t see any problems on my end

miguel-mconf · May 16, 2025, 5:12pm

As stated on the original post: This does not affect JSON visualization or the actual workflow, only the table visualization.

So yeah, it is an UI/front-end issue, that is only triggerable when you have +40 columns, so your example can’t reproduce it.

mohamed3nan · May 16, 2025, 5:17pm

Actually, it’s your example, I just copied and pasted it, then added a Set node to demonstrate that it’s probably a UI/front-end issue…

There are no issues with the backend or the actual workflow.

By the way, feel free to report it or open a GitHub issue here:

miguel-mconf · May 16, 2025, 5:23pm

Thank you for your attention. I’ve isolated the issue before posting it, and I was already sure it was an UI/front-end issue. That’s why I stated like that on the original post.

What I’ve tried to say is that your “modification” (or what I call, an example) doesn’t show the bug, and explained you why. The original post is now edited to have the data pinned so anyone can verify the bug is there.

I’ll open the issue, thank you.

mohamed3nan · May 16, 2025, 5:40pm

Thank you @miguel-mconf

Actually, there isn’t a UI/front‑end issue.

I took another look and noticed you’re not returning the same number of items:

You’re missing this key:

"an":"an"

So the undefined result actually makes sense in the table view.

If you add this key, bringing the total to 41, it looks correct:

miguel-mconf · May 16, 2025, 5:54pm

I’ve created a github issue, describing it in more details (and hopefully writing it more clearly):

github.com/n8n-io/n8n

UI/front-end: Table view breaks on multiple assymetrical columns

opened 05:49PM - 16 May 25 UTC

mprytoluk

in linear

### Bug Description When working with multiple items with +40 columns (when the… page breaks), having an item that doesn't have the same number of columns can trigger a UI bug on the table view, which shows the incorrect value for the first item on a column. I hope my provided example will make it clear. Related post on n8n forum: https://community.n8n.io/t/table-view-breaks-on-multiple-assymetrical-columns/116442 Please not that the issue is reproduced on the forum visualization as well. ### To Reproduce Test the workflow below: The table view incorrectly shows `undefined` as the value for the `ao` property on the first item. It should be `ao`. ![Image](https://github.com/user-attachments/assets/38163e46-fce9-4ef5-addf-d78bf695e132) The JSON output is correct, and the workflow functionality is not affected at all. ![Image](https://github.com/user-attachments/assets/d6327315-0d6c-457a-b50f-a3c4e14eb242) Note that it shows ` Some columns are hidden` when in fact all columns are there. If only the first item is processed, the `ao` column is not shown, which is correct. If a second item with one less property is added, the visualization breaks, so this hints that there is something wrong with the counting of number of properties that should be shown when items are asymmetrical (different number of columns). There is no issue when only one item is present. ![Image](https://github.com/user-attachments/assets/99b27306-2225-4333-97d9-2c050553f75b) Reproducible workflow: ``` { "nodes": [ { "parameters": { "jsCode": "return [\n {\n \"a\": \"a\",\n \"b\": \"b\",\n \"c\": \"c\",\n \"d\": \"d\",\n \"e\": \"e\",\n \"f\": \"f\",\n \"g\": \"g\",\n \"h\": \"h\",\n \"i\": \"i\",\n \"j\": \"j\",\n \"k\": \"k\",\n \"l\": \"l\",\n \"m\": \"m\",\n \"n\": \"n\",\n \"o\": \"o\",\n \"p\": \"p\",\n \"q\": \"q\",\n \"r\": \"r\",\n \"s\": \"s\",\n \"t\": \"t\",\n \"u\": \"u\",\n \"v\": \"v\",\n \"w\": \"w\",\n \"x\": \"x\",\n \"y\": \"y\",\n \"z\": \"z\",\n \"aa\": \"aa\",\n \"ab\": \"ab\",\n \"ac\": \"ac\",\n \"ad\": \"ad\",\n \"ae\": \"ae\",\n \"af\": \"af\",\n \"ag\": \"ag\",\n \"ah\": \"ah\",\n \"ai\": \"ai\",\n \"aj\": 'aj',\n \"ak\": \"ak\",\n \"al\": \"al\",\n \"am\": \"am\",\n \"an\": \"an\",\n \"ao\": \"ao\",\n },\n {\n \"a\": \"a\",\n \"b\": \"b\",\n \"c\": \"c\",\n \"d\": \"d\",\n \"e\": \"e\",\n \"f\": \"f\",\n \"g\": \"g\",\n \"h\": \"h\",\n \"i\": \"i\",\n \"j\": \"j\",\n \"k\": \"k\",\n \"l\": \"l\",\n \"m\": \"m\",\n \"n\": \"n\",\n \"o\": \"o\",\n \"p\": \"p\",\n \"q\": \"q\",\n \"r\": \"r\",\n \"s\": \"s\",\n \"t\": \"t\",\n \"u\": \"u\",\n \"v\": \"v\",\n \"w\": \"w\",\n \"x\": \"x\",\n \"y\": \"y\",\n \"z\": \"z\",\n \"aa\": \"aa\",\n \"ab\": \"ab\",\n \"ac\": \"ac\",\n \"ad\": \"ad\",\n \"ae\": \"ae\",\n \"af\": \"af\",\n \"ag\": \"ag\",\n \"ah\": \"ah\",\n \"ai\": \"ai\",\n \"aj\": \"aj\",\n \"ak\": \"ak\",\n \"al\": \"al\",\n \"am\": \"am\",\n \"ao\": \"ao\",\n },\n]" }, "type": "n8n-nodes-base.code", "typeVersion": 2, "position": [ 200, -20 ], "id": "ccf0cd55-7ccd-465e-a450-2e6412ca7d2c", "name": "Input" }, { "parameters": {}, "type": "n8n-nodes-base.manualTrigger", "typeVersion": 1, "position": [ 0, -20 ], "id": "ee776cda-45f2-4f40-b906-ddefe70d4996", "name": "When clicking ‘Test workflow’" } ], "connections": { "When clicking ‘Test workflow’": { "main": [ [ { "node": "Input", "type": "main", "index": 0 } ] ] } }, "pinData": { "Input": [ { "a": "a", "b": "b", "c": "c", "d": "d", "e": "e", "f": "f", "g": "g", "h": "h", "i": "i", "j": "j", "k": "k", "l": "l", "m": "m", "n": "n", "o": "o", "p": "p", "q": "q", "r": "r", "s": "s", "t": "t", "u": "u", "v": "v", "w": "w", "x": "x", "y": "y", "z": "z", "aa": "aa", "ab": "ab", "ac": "ac", "ad": "ad", "ae": "ae", "af": "af", "ag": "ag", "ah": "ah", "ai": "ai", "aj": "aj", "ak": "ak", "al": "al", "am": "am", "an": "an", "ao": "ao" }, { "a": "a", "b": "b", "c": "c", "d": "d", "e": "e", "f": "f", "g": "g", "h": "h", "i": "i", "j": "j", "k": "k", "l": "l", "m": "m", "n": "n", "o": "o", "p": "p", "q": "q", "r": "r", "s": "s", "t": "t", "u": "u", "v": "v", "w": "w", "x": "x", "y": "y", "z": "z", "aa": "aa", "ab": "ab", "ac": "ac", "ad": "ad", "ae": "ae", "af": "af", "ag": "ag", "ah": "ah", "ai": "ai", "aj": "aj", "ak": "ak", "al": "al", "am": "am", "ao": "ao" } ] }, "meta": { "templateCredsSetupCompleted": true, "instanceId": "72f1ea16a419b6b7665b6919b04c52751be5f8fdaa216af12b4f670d6bfb854a" } } ``` ### Expected behavior The table visualization should not show `undefined` for a variable that has a value. ### Operating System ubuntu ### n8n Version 1.85.4 ### Node.js Version v18.17.0 ### Database SQLite (default) ### Execution mode main (default)

miguel-mconf · May 16, 2025, 5:56pm

Dear mohamed.

Please checked my original post, as I’ve updated the example with pinned data.

If you compare the “JSON” and “table” views for the first item, I’m sure you’ll find the value for ao is inconsistent for the first item.

I’m 100% confident it is a UI issue at this point.

mohamed3nan · May 16, 2025, 5:59pm

I checked it, but I don’t see this key:

"an": "an"

The first item has 41 keys, and the second has 40 keys.

what am I missing here?!

miguel-mconf · May 16, 2025, 6:07pm

Yes, the an key is only present at the first item. That’s what triggers the bug. If the items have the same number of keys, the bug doesn’t occur. But the issue is not with this key, but with the key ao, which is present in both items, but doesn’t appear on the table visualization for the first item.

Please focus on the key ao and it will become clear.

mohamed3nan · May 16, 2025, 6:15pm

Got it, wow!
This is so confusing!
You’re absolutely right, I can see it now

Glad you reported it: UI/front-end: Table view breaks on multiple assymetrical columns · Issue #15476 · n8n-io/n8n · GitHub

I’m sure these replies will be helpful during reviews, so in the end, all our overthinking will have been totally worth it!

Thanks and have a nice day!

miguel-mconf · May 16, 2025, 6:20pm

Thank you for your attention!

I hope any errors in my English did not lead to any confusion.

mohamed3nan · May 16, 2025, 6:22pm

No worries at all, your message was perfectly clear!

I’m also using translation tools, so you’re definitely not alone

King_Samuel_David · May 16, 2025, 6:39pm

Nice find, hope they fix soon