topic Re: Help! Error: "Cannot read properties of undefined (reading '0')" in ArcGIS Experience Builder Questions

Help! Error: "Cannot read properties of undefined (reading '0')"

LayerItOn — Tue, 11 Nov 2025 23:31:34 GMT

One of my pages in exp.b. is throwing up this error when I go to check the pending items. No other pages are have this problem. If I duplicate the page (Viveros), the error persists (Viveros 2). Anyone experience this before?

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

NicoleJohnson — Wed, 12 Nov 2025 16:00:17 GMT

@LayerItOn, I've had this happen from time to time, but especially during the week or so after the October ArcGIS Online update. If you open your app in a new tab (you will lose your unsaved work), does the message go away?

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

Laura — Wed, 12 Nov 2025 16:07:22 GMT

Try to duplicate your whole EXB and start from a new one (essentially copy it and see if the error goes away)

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

LayerItOn — Wed, 12 Nov 2025 16:50:21 GMT

Error persists with copy 😞

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

LayerItOn — Wed, 12 Nov 2025 16:53:12 GMT

No luck, message still shows up for that page. Hmmm, I didn't think that it might be related to the recent update

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

Laura — Wed, 12 Nov 2025 16:56:05 GMT

hm when I've had the error support made me re-create it but to do for a whole page vs a widget is more of a hassle. I know it's simple but did you clear cache/history and try again?

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

LayerItOn — Wed, 12 Nov 2025 17:14:49 GMT

Darn, that is a good idea, but no luck. I tried to clear the cache/history, but still have the error.

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

NicoleJohnson — Wed, 12 Nov 2025 18:29:33 GMT

@LayerItOn, do you remember what you had done just before seeing the message? Most frequently this has happened to me right after setting a custom color somewhere on the style pane of a widget (but I've seen it after doing all sorts of things). I think maybe the JSON sometimes gets messed up, so if you can functionally reset it by going back to whatever widget you last interacted with and changing something about it (or deleting and reconfiguring it), maybe that will work?

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

LayerItOn — Wed, 12 Nov 2025 23:45:52 GMT

I deleted a hidden page, but that page was not linked to anything else in this page

Re: Help! Error: "Cannot read properties of undefined (reading '0')"

ShengdiZhang — Thu, 13 Nov 2025 01:35:59 GMT

Hi @LayerItOn ,

Could you share a sample app with me so we can take a close look at it?

Thanks,

Shengdi