# Error messages after "npm start"

**URL:** <https://pdfjs.community/t/error-messages-after-npm-start/1756>\
**Category:** Bug Reports\
**Tags:** pdfjs-express\
**Created:** [June 8, 2022, 11:29pm UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756 "2022-06-08T23:29:15Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![ballier](https://avatars.discourse-cdn.com/v4/letter/b/e8c25b/32.png) [@ballier](https://pdfjs.community/u/ballier)\
**Post date:** [June 8, 2022, 11:29pm UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756/1 "2022-06-08T23:29:15Z")

</div>

Hello,

after typing “npm start” I get the following messages. After that the sample files can not be opened. The circle stops at the half.

Best regards,  
Ralph

```javascript
> @pdftron/pdfjs-express-viewer@8.4.0 start /var/www/html/moodle4/pdftest
> npm run samples

> @pdftron/pdfjs-express-viewer@8.4.0 samples /var/www/html/moodle4/pdftest
> npm run server samples

> @pdftron/pdfjs-express-viewer@8.4.0 server /var/www/html/moodle4/pdftest
> node server.js $* "samples"

Listening at localhost:3000 (http://80.239.207.213:3000)
(node:437667) UnhandledPromiseRejectionWarning: Error: Exited with code 3
    at ChildProcess.cp.once.code (/var/www/html/moodle4/pdftest/node_modules/opn/index.js:85:13)
    at Object.onceWrapper (events.js:286:20)
    at ChildProcess.emit (events.js:198:13)
    at maybeClose (internal/child_process.js:982:16)
    at Socket.stream.socket.on (internal/child_process.js:389:11)
    at Socket.emit (events.js:198:13)
    at Pipe._handle.close (net.js:607:12)
(node:437667) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:437667) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

```

---

<div class="post-metadata">

**Author:** ![tgordon](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@tgordon](https://pdfjs.community/u/tgordon)\
**Post date:** [June 9, 2022, 3:52pm UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756/3 "2022-06-09T15:52:53Z")

</div>

Hello Ralph,

I was unable to reproduce this issue, here are the steps I took:

1. I downloaded the latest Zip file from here: [PDF.js Express Viewer Download & Integration | Documentation](https://pdfjs.express/documentation/get-started-viewer/manually)
2. I extracted the Zip file
3. I ran `npm install`
4. I then ran `npm run start`

Do these steps work for you?  
What version of Node are you using?  
What steps do you take to reproduce this issue?

Best regards,  
Tyler Gordon  
Web Development Support Engineer  
PDFTron

---

<div class="post-metadata">

**Author:** ![ballier](https://avatars.discourse-cdn.com/v4/letter/b/e8c25b/32.png) [@ballier](https://pdfjs.community/u/ballier)\
**Post date:** [June 9, 2022, 5:05pm UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756/4 "2022-06-09T17:05:18Z")

</div>

Hi Tyler,

unfortunately I do not know node etc. at all. My only concern is to make it easier to work with PDF files.

How can I find out which version node has?

Here again the complete and reproducible message after calling “npm run start”.

```javascript
root@ods13:/var/www/html/moodle4/pdftest# npm run start

> @pdftron/pdfjs-express-viewer@8.4.0 start /var/www/html/moodle4/pdftest
> npm run samples

> @pdftron/pdfjs-express-viewer@8.4.0 samples /var/www/html/moodle4/pdftest
> npm run server samples

> @pdftron/pdfjs-express-viewer@8.4.0 server /var/www/html/moodle4/pdftest
> node server.js $* "samples"

Listening at localhost:3000 (http://80.239.207.213:3000)
(node:465681) UnhandledPromiseRejectionWarning: Error: Exited with code 3
    at ChildProcess.cp.once.code (/var/www/html/moodle4/pdftest/node_modules/opn/index.js:85:13)
    at Object.onceWrapper (events.js:286:20)
    at ChildProcess.emit (events.js:198:13)
    at maybeClose (internal/child_process.js:982:16)
    at Socket.stream.socket.on (internal/child_process.js:389:11)
    at Socket.emit (events.js:198:13)
    at Pipe._handle.close (net.js:607:12)
(node:465681) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:465681) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

```

Best regards,  
Ralph

---

<div class="post-metadata">

**Author:** ![ballier](https://avatars.discourse-cdn.com/v4/letter/b/e8c25b/32.png) [@ballier](https://pdfjs.community/u/ballier)\
**Post date:** [June 9, 2022, 5:10pm UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756/5 "2022-06-09T17:10:33Z")

</div>

Hi Tyler,

Unfortunately I do not know node etc. at all. My only concern is to make it easier to work with PDF files.

How can I find out which version node has?

Here again the complete and reproducible message after calling “npm run start”.

```javascript
root@ods13:/var/www/html/moodle4/pdftest# npm run start

> @pdftron/pdfjs-express-viewer@8.4.0 start /var/www/html/moodle4/pdftest
> npm run samples

> @pdftron/pdfjs-express-viewer@8.4.0 samples /var/www/html/moodle4/pdftest
> npm run server samples

> @pdftron/pdfjs-express-viewer@8.4.0 server /var/www/html/moodle4/pdftest
> node server.js $* "samples"

Listening at localhost:3000 (http://80.239.207.213:3000)
(node:465681) UnhandledPromiseRejectionWarning: Error: Exited with code 3
    at ChildProcess.cp.once.code (/var/www/html/moodle4/pdftest/node_modules/opn/index.js:85:13)
    at Object.onceWrapper (events.js:286:20)
    at ChildProcess.emit (events.js:198:13)
    at maybeClose (internal/child_process.js:982:16)
    at Socket.stream.socket.on (internal/child_process.js:389:11)
    at Socket.emit (events.js:198:13)
    at Pipe._handle.close (net.js:607:12)
(node:465681) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:465681) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

```

Best regards,  
Ralph

---

<div class="post-metadata">

**Author:** ![ballier](https://avatars.discourse-cdn.com/v4/letter/b/e8c25b/32.png) [@ballier](https://pdfjs.community/u/ballier)\
**Post date:** [June 10, 2022, 8:28am UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756/6 "2022-06-10T08:28:31Z")

</div>

Hi Tyler,

look there. I can not write my answer.

Ralph

 ![](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/1X/02de77f9b39fdd56e03b77f7dcf8d011bcf2a054.png)

---

<div class="post-metadata">

**Author:** ![tgordon](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@tgordon](https://pdfjs.community/u/tgordon)\
**Post date:** [June 10, 2022, 4:54pm UTC](https://pdfjs.community/t/error-messages-after-npm-start/1756/7 "2022-06-10T16:54:57Z")

</div>

Hello Ralph,

You can check your node version with `node -v`  
Did you try the steps I outlined previously?

Best regards  
Tyler Gordon  
Web Development Support Engineer  
PDFTron