runs the main entry JavaScript file directly (npm/bin/npm-cli.js)

The main entry for npm is not npm-cli.js but rather lib/npm.js https://github.com/npm/cli/blob/ab0f0260e5b6333f98062fb2d9f4f9954d3ee6cd/package.json#L30 so I assume you mean that webstorm follows the bin setting, not main? But the package.json bin setting is what sets up the symlink into bin. So webstorm is just ignoring the symlink and hitting the configured file directly. Of course, this means you must be specially hardcoding the knowledge about which bin to follow, since npm has two (npx being the other)

Do you know if Webstorm would respect main if a bin isn't present?

Right, bin, not main. Yes, bin/npm-cli.js is hard-coded for npm currently.
WebStorm can respect bin property in future versions if needed.

We shouldn't use const because it's not fully supported until node 6. (Though this simple usage would probably work fine, at least to 0.10.)

@jasonkarns Do you need a fix for this? AFAIU, it will be available as a plugin, so the change probably goes to a different repo? Feel free to close this PR.

Nope, I left this comment before I found out that all this was hardcoded. If I could drop a package in that had this shim, I would think about it as a plugin. But hardcoding the location? And having the shim get added to the user's PATH? I don't think so.

So this will likely stay as a manual fix users of webstorm will have to do themselves.

But hardcoding the location?

@jasonkarns Agree, the hardcoded location is not nice as it requires to maintain magic filepath, bin/npm-cli.js in this case. Well, there hasn't been cases like this before when a bundled npm package couldn't be found by path to Node.js interpreter. So it worked well so far. In this case a clearer way to integrate would be to rely on bin property. Will be fixed in 2019.1 (https://youtrack.jetbrains.com/issue/WEB-36645).

And having the shim get added to the user's PATH?

Do you mean lib/node_modules/npm/bin should be added to user's PATH? It worked for me locally without adding new locations to the PATH.

So this will likely stay as a manual fix users of webstorm will have to do themselves.

Will it work for you if a package.json with bin property pointing to bin/npm-cli.js is added along with bin/npm-cli.js. Once IntelliJ/WebStorm supports bin property from package.json, JavaScript file location could be changed if there is a need for this.
Just not sure nodenv&IntelliJ/WebStorm users should suffer, because of hardcoded location which will be changed unlikely.

Regarding a package with that shim, IIUC, such a plugin was intended to be installed additionally to nodenv installation, so it won't work out-of-the-box?

Do you mean lib/node_modules/npm/bin should be added to user's PATH?

No! If we create a package named jetbrains-npm-shim that has bin/npm-cli.js, and we specify it's bin via: "bin": "./bin/npm-cli.js", then when the user installs this package via npm or yarn, then they will have jetbrains-npm-shim in their PATH. That's how the bin property works. It tells npm which files to symlink into PATH!

Since webstorm doesn't use PATH to find the npm script, then there's no need for it to be in PATH at all. But having this shim get added to PATH would be a negative side effect for webstorm user's who need to use the shim package.

The suggested managers list looks like:

@jasonkarns Sorry for the delay. Text Project in "Package manager" field of the Npm run/debug configuration means that the package manager specified in "Settings | Languages & Frameworks | Node.js and NPM" should be used. Please check how "Package manager" is specified in "Settings | ... | Node.js and NPM". Looks like it's empty there.

Right. I thought I read somewhere that ../lib/node_modules/npm/bin/npm-cli.js would be picked up automatically if it existed relative to the node interpreter. It was definitely found by webstorm automatically (I can see it resolved the path and version number in the drop-down list), but I still had to explicitly select it when attempting to run a script.

I was thinking that it would be used automatically if found, without need to explicitly select it from the list.

@jasonkarns According to your screenshots, the "npm" reference was resolved correctly to /usr/local/var/nodenv/lib/node_modules/npm. But the "Project" reference is unresolved unexpectedly. Could you please attach a screenshot of "Settings | Languages & Frameworks | Node.js and NPM" with expanded "Package manager" field?
Looks like a bug. Your file structure is still like described in #129 (comment), right?

@segrey I cleared it out manually hoping to simulate a "fresh install". apparently I just needed to restart webstorm and it selected that one automatically. all good 👍

I've confirmed that webstorm doesn't actually need any of this (strictly) and works as long as bin/npm-cli.js exists in the folder that's configured as the "package manager". I'm not against including this file, but if so, we should actually use it by declaring the main/bin file appropriately.

package.json file was added as WebStorm checks its presence. It can be empty. Otherwise, lib/node_modules/npm won't be considered as a package.

I dropped bin/npm-cli.js in a random folder and it works, without any package.json. Whatever folder you point webstorm to for npm, as long as it has bin/npm-cli.js it works. (Which is nice for a workaround, but a dreadful sign for what this means per the implementation.)

Strange, it doesn't work for me without package.json (possibly empty).

The workaround as documented works for me with webstorm 2018.3. https://github.com/nodenv/nodenv/wiki/FAQ#workaround

The workaround just adds bin/npm-cli.js to the nodenv root directory, and requires user to point webstorm to the nodenv root directory as the package manager. That was all that was necessary for it to work for me. No lib/node_modules, no package.json, etc. Just bin/npm-cli.js in the directory configured as the package manager.

Ah, right, it works, because $(nodenv root) was specified as npm package directory manually in UI, and there is $(nodenv root)/package.json file related to nodenv itself.
The workaround with lib/node_modules/npm/{package.json, bin/npm-cli.js} won't require users to specify "Package manager" field manually, it will be inferred automatically if "Node interpreter" points to $(nodenv root)/shims/node.

I have a custom location for $NODENV_ROOT, so there is no package.json in mine:

$ cd `nodenv root`
$ pwd
/usr/local/var/nodenv
$ ls
bin/              default-packages  nodenv.d/         shims/            versions/
cache/            etc/              plugins/          sources/
$ ls bin/
npm-cli.js

The workaround with lib/node_modules/npm/{package.json, bin/npm-cli.js} won't require users to specify "Package manager" field manually, it will be inferred automatically if "Node interpreter" points to $(nodenv root)/shims/node.

That's good to know but it would be a "weird" install location for nodenv users. nodenv plugins live in $(nodenv root)/plugins. My intention for the shim plugin is to be installable as a global npm package or as a nodenv plugin. But both installations would require manually specifying its location via webstorm package manager, since neither approach would end up in $(nodenv root)/lib/node_modules/...

Right, I forget that an absolute path to npm package is specified in UI. Existence of package.json is checked only when inferring npm package automatically by node interpreter location or npm executable. Manually specified npm packages are not checked for package.json.