"Cannot find module 'npm'"

[timdp]

I use npm@3.1.2. Using grunt-aws-lambda gives me:

Loading "lambda_package.js" tasks...ERROR
>> Error: Cannot find module 'npm'
>>     at Function.Module._resolveFilename (module.js:336:15)
>>     at Function.Module._load (module.js:278:25)
>>     at Module.require (module.js:365:17)
>>     at require (module.js:384:17)
>>     at Object.module.exports (node_modules\grunt-aws-lambda\tasks\lambda_package.js:14:15)

Looks like require('npm') no longer works by default with npm 3.

npm i npm@3.1.2 fixes it, so you can probably just include npm in the dependencies. No idea how you would elegantly pass the version of the globally installed npm though. A postinstall hook would work, I guess.

[Tim-B]

Hi @timdp, thanks for the report!

Can you confirm you're using the latest version of this plugin (ie. 0.8.0)? npm was added to the devDependencies a few versions back which solved some similar issues a few people were having.

I also installed NPM 3.1.2 and it seems to be working okay for me.

[timdp]

Thanks for the quick response!

Won't devDependencies only get installed if I install my own module with --dev? That's not something I'm eager to do.

Is there a reason why it's not a regular dependency?

[Tim-B]

My understanding is that devDependencies should get installed by a regular npm install unless you add the --production flag.

If you are using the latest version you could try moving it to regular dependencies, I'd be interested to know if that helps.

[timdp]

Pretty sure that that's not how it works. Installing devDependencies for all dependencies by default would mean a hell of a lot of modules to install. For example, for every module that depends on PhantomJS for browser testing, you'd then unzip PhantomJS again. Particularly with npm 2's non-flattened node_modules folder, you'd waste a lot of disk space on modules that never get used, since you'd never run the tests for your dependencies; that's the author's job.

I verified this by just running npm init && npm i --save grunt grunt-aws-lambda in a new folder. It created neither node_modules/npm nor node_modules/grunt-aws-lambda/node_modules/npm. With --save-dev rather than --save, I got the same result. The only difference between those two flags is how it updates package.json, I think.

[timdp]

Maybe you're getting confused by how npm i works from inside your module's folder? It will install both dependencies and devDependencies for ./package.json, but not for their dependencies.

[Tim-B]

Yeah you're right, I was thinking of the situation where the module was being installed directly as opposed to being installed as a dependency.

Truth be told I was never able to replicate the issue, however someone submitted a pull request saying adding npm to devDependencies fixed it for them. The change didn't cause any tests to fail and didn't seem to have any side effects so I accepted it.

So does adding npm as a regular dependency help your issue?

[timdp]

It most likely would. I'm at work now, but I'll test soon.

[peterfox]

I had an issue with this on my Mac, just had to add
export NODE_PATH='/usr/local/lib/node_modules'

to my ~/.bash_profile and it worked fine afterwards.

[timdp]

That sounds like a different issue to me.

[timdp]

Making npm a regular dependency worked for me.

I initially tried with npm@^3.2.0, but that failed. I'll make a new issue for documenting my findings.