# Useage of contrib-npm

**URL:** <https://discourse.nodered.org/t/useage-of-contrib-npm/67449>\
**Category:** General\
**Created:** [7 September 2022 21:49 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449 "2022-09-07T21:49:13Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![smitterer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/smitterer/32/59179_2.png) [@smitterer](https://discourse.nodered.org/u/smitterer)\
**Post date:** [7 September 2022 21:49 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/1 "2022-09-07T21:49:13Z")

</div>

Hi!

I'd like to use the npm node ([node-red-contrib-npm (node) - Node-RED](https://flows.nodered.org/node/node-red-contrib-npm)) to be able to use pdf-merger-js ([pdf-merger-js - npm](https://www.npmjs.com/package/pdf-merger-js)).

Unfortunately, I always get errors like `TypeError: func is not a function` or similar, depending on how I connect the individual nodes in the following flow:

```auto
[{"id":"ae6cb40ae0efa2ed","type":"npm","z":"4b453fb457938d95","name":"pdf-merger-js","func":"const PDFMerger = require('pdf-merger-js');\n\nvar merger = new PDFMerger();\n\n(async () => {\n await merger.add('pdf1.pdf'); //merge all pages. parameter is the path to file and filename.\n await merger.add('pdf2.pdf');\n\n await merger.save('merged.pdf'); //save under given name and reset the internal document\n})();\nreturn npm_module(msg.payload);","npm_module":"pdf-merger-js","module_style":"custom","msg_payload":"return_val","function_name":"","x":470,"y":600,"wires":[["07e72953e011a95c"]]},{"id":"24b90b147213d017","type":"inject","z":"4b453fb457938d95","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":200,"y":600,"wires":[["ed2cb1df163e8109"]]},{"id":"07e72953e011a95c","type":"debug","z":"4b453fb457938d95","name":"debug 36","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":660,"y":560,"wires":[]},{"id":"ed2cb1df163e8109","type":"npm","z":"4b453fb457938d95","name":"pdf-lib","func":"// NPM module exposed as variable, npm_module\nreturn npm_module(msg.payload);","npm_module":"pdf-lib","module_style":"cstr","msg_payload":"callback_error","function_name":"","x":230,"y":540,"wires":[["102cd5d700f07c78"]]},{"id":"102cd5d700f07c78","type":"npm","z":"4b453fb457938d95","name":"pdf-merger-js install","func":"// NPM module exposed as variable, npm_module\nreturn npm_module(msg.payload);","npm_module":"pdf-merger-js","module_style":"cstr","msg_payload":"return_val","function_name":"","x":430,"y":540,"wires":[["ae6cb40ae0efa2ed"]]}]

```

Any idea how I am able to get this to work?

I'd also appreciate another solution on how I would be able to generate a template output per injected payload to store each output as a page in one file using [node-red-contrib-pdf (node) - Node-RED](https://flows.nodered.org/node/node-red-contrib-pdf) instead of the approach of combining the resulting pdfs.

Thanks!

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [8 September 2022 05:08 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/2 "2022-09-08T05:08:11Z")

</div>

> I'd like to use the npm node

You don't have to use that node anymore, it has been integrated into the function node into the setup tab.

 ![SCR-20220908-9wg](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/7/17712ef050ca7201629d136248dadd17a1c58722.png)

---

<div class="post-metadata">

**Author:** ![smitterer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/smitterer/32/59179_2.png) [@smitterer](https://discourse.nodered.org/u/smitterer)\
**Post date:** [8 September 2022 06:29 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/3 "2022-09-08T06:29:55Z")

</div>

Thanks, but this still requires me to add it to settings.js or am I wrong? ([Writing Functions : Node-RED](https://nodered.org/docs/user-guide/writing-functions#loading-additional-modules))

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [8 September 2022 06:32 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/4 "2022-09-08T06:32:42Z")

</div>

It needs to be enabled in settings.js:

> setting `functionExternalModules` to `true` in you _settings.js_ file

restart node-red and you should be able to use any npm package within the function node.

---

<div class="post-metadata">

**Author:** ![smitterer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/smitterer/32/59179_2.png) [@smitterer](https://discourse.nodered.org/u/smitterer)\
**Post date:** [8 September 2022 06:38 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/5 "2022-09-08T06:38:48Z")

</div>

hm this is already set to true.

I added the modules:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/c/0c04b7bb7590670f5c58d30f4f3a5ee3fda61570.png)

On message now looks:

```auto
const PDFMerger = require('pdfMergerJs');

var merger = new PDFMerger();

(async () => {
  await merger.add('pdf1.pdf'); //merge all pages. parameter is the path to file and filename.
  await merger.add('pdf2.pdf');

  await merger.save('merged.pdf'); //save under given name and reset the internal document
})();
return msg.payload;

```

Getting the error:

```auto
ReferenceError: require is not defined (line 1, col 19)

```

Should it be requrire('pdf-merger-js'); (original node name) or requrie('pdfMergerJs') from "Import as" in module settings?  
Or what am I missing here?

Thanks

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [8 September 2022 06:40 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/6 "2022-09-08T06:40:54Z")

</div>

You can remove the require, as that is what the setup tab invokes.

`const merger = new pdfMergerJs()`

---

<div class="post-metadata">

**Author:** ![smitterer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/smitterer/32/59179_2.png) [@smitterer](https://discourse.nodered.org/u/smitterer)\
**Post date:** [8 September 2022 10:40 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/7 "2022-09-08T10:40:38Z")

</div>

You are my absolute hero.

Her is the final, working code:

```auto
const merger = new pdfMergerJs();

(async () => {
  await merger.add('/media/file1.pdf'); //merge all pages. parameter is the path to file and filename.
  await merger.add('/media/file2.pdf');

  await merger.save('/media/merged.pdf'); //save under given name and reset the internal document
})();
return msg

```

As I need to change the function based on a list of files in a folder (and I need support with that but it has nothing to do with contrib-npm), I'll create a new topic on that.

Thanks!

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [22 September 2022 10:40 UTC](https://discourse.nodered.org/t/useage-of-contrib-npm/67449/8 "2022-09-22T10:40:54Z")

</div>

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