Play nice with transpilers by using variable requires (fixes #345)

[blahah]

As discussed in #345 this PR moves all conditional requires in lib/config.js to use a variable module name. This allows transpilers like Webpack to properly resolve the dependency graph.

[lorenwest]

Javascript hoists variables, and having individual var dep gives the misleading impression that these are different things, when they are all the same variable.

A better pattern would be to define var dep = undefined; at the top of the function and use that variable without (misleadingly) re-defining it in each instance.

Even better would be to have a block at the top of the file like this

// Define soft dependencies so transpilers don't include everything
var ICED_COFFEE_SCRIPT = "iced-coffee-script";
var JS_YAML = "js-yaml"
...

Then simply use these variables instead of the hardcoded strings require(ICED_COFFEE_SCRIPT);

[blahah]

+1 to that. I blindly implemented the isolated solution given for one variable in the issue thread. I'll push an update now.

[jonohodgson]

I've taken this config.js but still getting
ERROR in ./~/config/lib/config.js
Module not found: Error: Cannot resolve module 'fs'

Is this working for others?

[blahah]

@jonohodgson I eventually discovered that it's extremely hard to get node-config working with Webpack (or any transpiler) in the browser environment in any meaningful way. This is because there is no fs module in the browser, and it's impossible to fully implement one.

In Webpack you can avoid that specific error using node: { fs: "empty" } (see the Webpack docs) which will give a no-op on any fs call. However, you will still face the problem that your config file will not be found by node-config, because it can't access the real filesystem. You can hack your config files into an in-memory filesystem polyfill, but at this point you may as well just have a config object in memory.

Ultimately we settled on exposing a shimmed CONFIG global using Webpack EnvironmentPlugin. An alternative that we considered but ultimately didn't need was node-config-loader.

[botagar]

Hi. I was wondering what the progress of this PR is, and If I should create a similar one if this branch is not being worked on anymore.
This fix is something I need, and I would like the freedom to be able to clear my packages and re-install at will.

~~Cheers~!~~

Edit: Nevermind, I think I see the issue being face above. Sorry.

[jdmarshall]

This PR appears to be answered by #118

[markstos]

@jdmarshall #118 is an old issue about CSON support. Try again?

[jdmarshall]

Yeah looks like they were referencing their own ticket.

#557

[markstos]

Given the comment about that says essentially "this wasn't going to work in the end anyway": #358 (comment) I'm closing this.