Node: Add default module search paths to package.json

Created on 3 Oct 2017 · 15Comments · Source: nodejs/node

I'm using TypeScript, with my source files in src/ and outputting to dist/. I have modules in src/modules/ and some other stuff in src/scripts/. The directory structure is maintained when TypeScript transpiles to JavaScript in dist/. However, the import... statements are transpiled to require() statements with the (non-relative) paths unchanged.

In TypeScript, I can refer to my modules without having to use messy relative paths by setting baseUrl in tsconfig.json. If I set it to ./src, I can then import my modules with something like:
import * as myModule from "modules/myModule";

However when that is transpiled to the Node.js equivalent:
const my_module_1 = require("modules/myModule");

... Node.js doesn't find the module because the file pulling in the module is in src/scripts. Wouldn't it be nice if you could just add module search paths to the beginning of Node's paths list by just having a moduleSearchPaths property in package.json (@refack suggested using .npmrc instead)? Then the first place Node would search would be those paths and I could just say:

    ...
    "moduleSearchPaths": [
        "./dist"
    ]
    ...

... making Node first search for dist/modules/myModule.js - and it would work.

By the way, I know you can set the NODE_PATH env variable to do this but I think that's a nasty solution because I always try to avoid using env variables. They don't translate well between different environments.

feature request module

Source

jez9999

👍16

Most helpful comment

My understanding is that NODE_PATH=./path/to/somewhere node file.js is the only practical means of specifying a path.

I do this because

const myModule = require('static-path-to/my-module')
````
is much cleaner than 
```javascript
const myModule = require('../../../../../omg/../relative-path-to/my-module')

which is brittle because it may break when the containing file moves or when copied to another file; and it just looks terrible.

If NODE_PATH is going away, we need an equivalent. A --node_path="./path/to/somewhere" flag or a "paths": "./path/to/somewhere" package.json key/value would work just fine in my case. Either would also work for Windows unlike my current solution. See https://github.com/nodejs/node-v0.x-archive/issues/4609 by @ForbesLindesay.

BrandonZacharie on 4 Jan 2018

👍14

All 15 comments

I think this is unlikely to gain traction because I see this as a similar request brought up during the ES modules implementation discussion(s), which was voted down by the TSC. I think this just unnecessarily complicates the lookup algorithm even further, when the lookup algorithm is already fairly complicated.

mscdex on 3 Oct 2017

So there's literally no way to get away from relative paths? This seems like a really basic issue to me.

jez9999 on 3 Oct 2017

There is a way that I've used a few times. You can create a src/node_modules directory and put your files in it.

targos on 4 Oct 2017

Yeah that does work. Feels like a hack though. People will think it should be for NPM modules.

jez9999 on 4 Oct 2017

It's not really a hack though - node_modules is a _node_ thing. npm just happens to install to it so that things work out of the box.

Fishrock123 on 5 Oct 2017

But is it really a good idea to dictate that you have a src/node_modules directory structure rather than have what you want and point to it?

jez9999 on 5 Oct 2017

Yes, IMO. It means there is One And Only One Way to do it.

Right now the rule is 'look in node_modules' and every developer knows that.

bnoordhuis on 6 Oct 2017

Except that it isn't because it looks in a bunch of different places including the NODE_PATH variable.

jez9999 on 6 Oct 2017

@jez9999 NODE_PATH is deprecated and does not work w/ ESM loader. If someone is relying on it you should feel encouraged to tell them to move off of it.

bmeck on 11 Oct 2017

And switch to having a second ugly node_modules directory in their source tree. Not exactly something I can recommend either.

jez9999 on 11 Oct 2017

I have to agree with @jez9999. I can see some of the philosophical/implementation issues with a package.json configurable paths option, but it seems like a common issue that many devs have with Node, no? And it likely _is_ solvable by smarter minds than mine? In any case, would be a fantastic feature for a common usecase!

rafegoldberg on 3 Nov 2017

My understanding is that NODE_PATH=./path/to/somewhere node file.js is the only practical means of specifying a path.

I do this because

const myModule = require('static-path-to/my-module')
````
is much cleaner than 
```javascript
const myModule = require('../../../../../omg/../relative-path-to/my-module')

which is brittle because it may break when the containing file moves or when copied to another file; and it just looks terrible.

BrandonZacharie on 4 Jan 2018

👍14

Put into https://github.com/nodejs/node/projects/13 backlog

refack on 11 Nov 2018

At the top of your script, use the following to add a new search path for modules search.
module.paths.push('[MEW_PATH');

For example:
module.paths.push('../../../../../omg/../relative-path-to');
const myModule = require('my-module')

RoyeA on 27 Dec 2019

@RoyeA I presume, it'll work for scripts, but not for programs. module is not a global but a local-per-module.

On the other hand, if it was truely global (like NODE_PATH), it'll lead to broken code in other modules just because they're may be unaware of that certain path modification.