Live preview `onclick` event fails as a blitz, but works in bolt.new

[selfcommit]

Describe the bug

On click of this example button:

The follow error message returns:

Something about the live preview in StackBlitz seems to want valid JSON.
Interestingly, this same code runs without issue inside of bolt.new

Link to the blitz that caused the error

https://stackblitz.com/edit/sb1-sptuktul?file=index.html,tsconfig.node.json

Steps to reproduce

1. Navigate to a same project with an onclick button (Example: https://stackblitz.com/edit/sb1-sptuktul?file=index.html,tsconfig.node.json)
2. Open the preview mode, and click the button
3. The button event will fail, with an error in the js console.

Expected behavior

The onclick function should be able to render the event without error.

Parity with Local

• I have run the project in my local machine and I could not reproduce the issue.

Screenshots

Platform

Browser name  = Chrome
Full version  = 134.0.0.0
Major version = 134
navigator.appName = Netscape
navigator.userAgent = Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36
performance.memory = {
  "totalJSHeapSize": 134952544,
  "usedJSHeapSize": 115767592,
  "jsHeapSizeLimit": 4294705152
}
Hash = 495c5120

Additional context

No response

[d3lm]

Thanks for reporting this issue.

It seems I can't open the project you provided. Does it still exist and if yes is it public?

[selfcommit]

Thanks for reporting this issue.

It seems I can't open the project you provided. Does it still exist and if yes is it public?

Sorry about that - it should be public now.

[d3lm]

Thanks! This is actually not an issue and the same behavior locally. If you don't start the server that listens for /api/hello then it will just respond with the index.html which seems to be the behavior from Express, since it's also on the same port. And since it's HTML you can't call .json() on it. If you run node server.js in another terminal and hit that button again it works as expected.

[selfcommit]

That tracks! I kicked off the server locally so didn’t see that on repeat. The only issue then is unexpected behavior. It wasn’t clear, to me, that the init experience differed between bolt and stackblitz. Thanks for your time - the reasoning is well explained and I’m fine with closing this issue.

…

On Mon, Mar 17, 2025 at 6:09 AM Dominic Elm ***@***.***> wrote: Thanks! This is actually not an issue and the same behavior locally. If you don't start the server that listens for /api/hello then it will just respond with the index.html which seems to be the behavior from Express, since it's also on the same port. And since it's HTML you can't call .json() on it. If you run node server.js in another terminal and hit that button again it works as expected. — Reply to this email directly, view it on GitHub <#1770 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAH3HJTVSSCRSEU2XLNFA2D2U2NOLAVCNFSM6AAAAABYYW6KS2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDOMRYHA4TIMZTGU> . You are receiving this because you authored the thread.Message ID: ***@***.***> [image: d3lm]*d3lm* left a comment (stackblitz/webcontainer-core#1770) <#1770 (comment)> Thanks! This is actually not an issue and the same behavior locally. If you don't start the server that listens for /api/hello then it will just respond with the index.html which seems to be the behavior from Express, since it's also on the same port. And since it's HTML you can't call .json() on it. If you run node server.js in another terminal and hit that button again it works as expected. — Reply to this email directly, view it on GitHub <#1770 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAH3HJTVSSCRSEU2XLNFA2D2U2NOLAVCNFSM6AAAAABYYW6KS2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDOMRYHA4TIMZTGU> . You are receiving this because you authored the thread.Message ID: ***@***.***>