Error: Cannot find module 'mqtt'

[Xecu114]

Hello,

i try to create a custom node and use the mqtt js library (is also used by the mqtt nodes from node-red).
The big problem is:
"Cannot find module 'mqtt'"
I tried following things:
npm install mqtt --save
npm install mqtt -g
and if i look for mqtt it is listed both in my project folder as in the global folder...
I also added mqtt to the depndencies but nothing worked...
Does anyone have any ideas what could be the problem?

[Colin]

If you need a module then that should be declared in the node's package.json. Then when you install the node, npm will automatically install the dependency (if necessary) and make it available.

[Xecu114]

it is in my dependencies... all modules i try to use are not working...

and i also changed the version number bbut didn't work either... i think there is a problem that my custom nodes can't access the modules in the roaming folder... but i have no idea how to fix this.
My Node-RED Project is located here: C:\Users\JSHR.node-red
My npm files and node-red it self are located: here C:\Users\JSHR\AppData\Roaming\npm

[Steve-Mcl]

@Xecu114

npm install mqtt --save

From inside your custom node path?

@Xecu114

npm install mqtt -g

Dont do that.

@Xecu114

and if i look for mqtt it is listed both in my project folder as in the global folder.

Because you did npm install mqtt -g

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You should simply...

• Setup your custom nodes project folder with necessary files (package.json, your-node.js, your-node.html)
• For any module that is required by your contrib node, from the base path of your custom node (e.g. C:\my-projects\my-contrib-node) install the requires using npm -i mqtt (or whatever)
• Ensure your project folder has a .gitignore file and exclude node_modules etc

Once project is ready to test, in your node-red folder (e.g. cd c:\users\JSHR\.node-red), install your node...

• npm install C:/my-projects/my-contrib-node

Restart node-red after every change to your source.

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From that point on, C:/my-projects\my-contrib-node will be sym-linked to c:\users\JSHR\.node-red\node_modules\my-contrib-node. That means any files you change/delete in c:\users\JSHR\.node-red\node_modules\my-contrib-node will be changed/deleted from C:/my-projects\my-contrib-node

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alternatively, if you want step debug in vscode - follow this