SyntaxError: Unexpected token T in JSON at position 0 WHile building the website

[AnasAitzouinet]

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Hi , im trying to build my website and i get this error, i tried a lot of thing but nothing were helpful :

Which area(s) of Next.js are affected? (leave empty if unsure)

No response

Link to the code that reproduces this issue

https://github.com/AnasAitzouinet/my-eco

To Reproduce

info - Collecting page data .SyntaxError: Unexpected token T in JSON at position 0
at JSON.parse ()
at parseJSONFromBytes (node:internal/deps/undici/undici:6498:19)
at successSteps (node:internal/deps/undici/undici:6472:27)
at node:internal/deps/undici/undici:1145:60
at node:internal/process/task_queues:140:7
at AsyncResource.runInAsyncScope (node:async_hooks:204:9)
at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Build error occurred
Error: Failed to collect page data for /Product/[id]
at C:\Users\anasa\OneDrive\Documents\Git\Garboz\my-eco\node_modules\next\dist\build\utils.js:1055:15
at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
type: 'Error'

Describe the Bug

im just tryin the website by next build and i get this error even thought i did alot of fixes but nothing worked

Expected Behavior

trying to build it

Which browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

[ascholz81]

I'm seeing this in a deployed application. Currently our leading thought is using Node 18. This stack seems to be very low level in Node itself.

The error is random. All api and ANY JSON.parse calls are wrapped in try/catch. I can't reproduce it locally.

[crava-logico-srl]

Same happened to us.
Production deployed app, just upgraded to next 13.2.4

• next: 13.2.4
• node: 18.15.0

next app sends back 500 error, and the only recurrent log in pm2 logs is

SyntaxError: Unexpected token T in JSON at position 0
at JSON.parse ()
at parseJSONFromBytes (node:internal/deps/undici/undici:6498:19)
at successSteps (node:internal/deps/undici/undici:6472:27)
at node:internal/deps/undici/undici:1145:60
at node:internal/process/task_queues:140:7
at AsyncResource.runInAsyncScope (node:async_hooks:204:9)
at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

[Svisstack]

Same here, how you guys made this work?

[AlexandreBourdeaudhui]

Same here, how you guys made this work?

Dunno if that can help you, but, switched the Node.js version, from 18.15, to 16.13... Give me more details on the unexpected error...
With Node.js 18.XX, i have an error log "Unexpected token < in JSON at position 2"
With Node.js 16.13, i have another error log "FetchError: invalid json response body at https://xxx-site.httpd.docker.localhost/user/2/edit, reason: Unexpected token < in JSON at position 2". With the (new) stacktrace i logged (/opt/nextjs/node_modules/next/dist/compiled/node-fetch/index.js:1:51255) and saw i got an HTML output.

[tamvm]

any suggestion to fix this with nextjs 13.x, I have tried with the latest nextjs version 13.4.2 but it still doesn't work

[Ionito]

same thing is happening to me, any idea?

[mcapodici]

I am getting the same error. What is a stable version of NextJS to downgrade to?

Edit: this one was my fault, ignore!

[AndreChavs]

I have the same error
I'm using versions:

Error: Failed to collect page data for /[id]
at ...\node_modules\next\dist\build\utils.js:1055:15
at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
type: 'Error'
}
node - 18.7.0
Next - 13.2.4

[Surfer-Alex]

same here，

SyntaxError: Unexpected token < in JSON at position 0

21:09:13.269 | at JSON.parse ()
21:09:13.269 | at parseJSONFromBytes (node:internal/deps/undici/undici:6498:19)
21:09:13.269 | at successSteps (node:internal/deps/undici/undici:6472:27)
21:09:13.270 | at node:internal/deps/undici/undici:1145:60
21:09:13.270 | at node:internal/process/task_queues:140:7
21:09:13.270 | at AsyncResource.runInAsyncScope (node:async_hooks:204:9)
21:09:13.271 | at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
21:09:13.271 | at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

[hammadqurashi]

Works fine for me in dev mode but when deploying it to vercel it gives the error:

SyntaxError: Unexpected token T in JSON at position 0

17:06:22.809 | at JSON.parse ()
17:06:22.810 | at parseJSONFromBytes (node:internal/deps/undici/undici:6571:19)
17:06:22.810 | at successSteps (node:internal/deps/undici/undici:6545:27)
17:06:22.811 | at node:internal/deps/undici/undici:1211:60
17:06:22.811 | at node:internal/process/task_queues:140:7
17:06:22.812 | at AsyncResource.runInAsyncScope (node:async_hooks:203:9)
17:06:22.812 | at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
17:06:22.813 | at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

[jomefavourite]

Mine is * SyntaxError: Unexpected token o in JSON at position 1*

[jomefavourite]

I fixed this issue by using the Function method

// Instead of JSON.parse(someVar) use this instead
Function("return " + someVar)

Though I don't know if there's any security risk using the Function method, but it parses the JSON string (someVar) to an object.

[rodolphoasb]

Same error here! I can't receive a simple POST request on my endpoints without seeing this error.

- error SyntaxError: Unexpected number in JSON at position 1
    at JSON.parse (<anonymous>)
    at parseJSONFromBytes (node:internal/deps/undici/undici:6571:19)
    at successSteps (node:internal/deps/undici/undici:6545:27)
    at node:internal/deps/undici/undici:1211:60
    at node:internal/process/task_queues:140:7
    at AsyncResource.runInAsyncScope (node:async_hooks:203:9)
    at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

[ArthurDias01]

SyntaxError: Unexpected token < in JSON at position 0

15:13:37.473 | at JSON.parse ()
15:13:37.474 | at parseJSONFromBytes (node:internal/deps/undici/undici:6571:19)
15:13:37.474 | at successSteps (node:internal/deps/undici/undici:6545:27)
15:13:37.474 | at node:internal/deps/undici/undici:1211:60
15:13:37.474 | at node:internal/process/task_queues:140:7
15:13:37.474 | at AsyncResource.runInAsyncScope (node:async_hooks:203:9)
15:13:37.474 | at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
15:13:37.474 | at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Has anyone found a solution?
(reproducible src code)
https://github.com/ArthurDias01/arthurdiasdev/tree/85b4985f6c36db3d04dc96de4ecd59504d2d2462