# find a error when build mediasoup-demo
**URL:** https://mediasoup.discourse.group/t/find-a-error-when-build-mediasoup-demo/4192
**Category:** Deployment & Scalability
**Created:** [May 20, 2022, 10:26am UTC](https://mediasoup.discourse.group/t/find-a-error-when-build-mediasoup-demo/4192 "2022-05-20T10:26:42Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@avdance](https://mediasoup.discourse.group/u/avdance)
#### Post date: [May 20, 2022, 10:26am UTC](https://mediasoup.discourse.group/t/find-a-error-when-build-mediasoup-demo/4192/1 "2022-05-20T10:26:42Z")
I pull newest mediasoup-demo from github and deployed it on my host, but when I build the client in app dir using ‘gulp dist’, I get a error , the error message is " error Unexpected use of file extension “json” for “./package.json” import/extensions". I dont understand why
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### Author:  [@avdance](https://mediasoup.discourse.group/u/avdance)
#### Post date: [May 20, 2022, 10:57am UTC](https://mediasoup.discourse.group/t/find-a-error-when-build-mediasoup-demo/4192/2 "2022-05-20T10:57:50Z")
Now, I have konwed why gulp report this error. Shuold modify gulpfile.js file from “require(’./packet.json’)” to “require(’./packet’)”