Add self-link script as part of the pretest setup

[Andarist]

This should link (if needed) automatically before running tests

[haltcase]

Thanks for this @Andarist! Unfortunately this is unix only and wouldn't work on Windows. Would you be willing to adapt this to a more portable solution? If not I'd like to at least document the differences in build steps between platforms.

[Andarist]

Thanks for this @Andarist! Unfortunately this is unix only and wouldn't work on Windows. Would you be willing to adapt this to a more portable solution? If not I'd like to at least document the differences in build steps between platforms.

I could probably try to unify it. Ideally I'd hide in a simple CLI tool using node APIs (I have no idea how to write powershell scripts, node APIs should take care of platform differences for me). Do you have an idea for the API of such a tool?

[haltcase]

how to write powershell scripts

I'm starting to use it a lot... it's awesome.

We can probably just do a small script at the root called .bootstrap.js, something like (untested):

const { existsSync } = require('fs')
const { join } = require('path')
const { execFileSync } = require('child_process')

const pkgPath = join('node_modules', process.env.npm_package_name)

if (!existsSync(pkgPath)) {
  execFileSync('npm', ['link'])
  execFileSync('npm', ['link', process.env.npm_package_name])
}

And then in package.json:

{
  "scripts": {
    "pretest": "node .bootstrap.js && npm run build",
    "test": "ava"
  }
}

[Andarist]

I was worried about the fact that npm link runs a prepare scripts (so most likely build) and that would cause double build when running it for the first time - but I guess this is not really that much of a concern as it won't happen every time 🤔

Gonna prepare this thing some time later and adjust the PR!

[haltcase]

@Andarist great. Double build shouldn't be a problem but you could maybe make .bootstrap.js exit with an error code after linking, then use || or && somehow to prevent the npm run build step in the package script from triggering.

if (!existsSync(pkgPath)) {
  execFileSync('npm', ['link'])
  execFileSync('npm', ['link', process.env.npm_package_name])
  process.exitCode = 1
}

[Andarist]

I was thinking about it (although werent sure if || is correct for powershell), but any exit code other than 0 would kinda mean some kind of error (as far as i know, not an expert in bash semantics though), so it wouldnt be quite correct to exit with 1 (or other number)

[haltcase]

I was thinking about it (although werent sure if || is correct for powershell)

It's not but npm scripts are run with cmd on Windows, not PowerShell, and both || and && would accomplish the same thing on Windows as on macOS/Linux.

any exit code other than 0 would kinda mean some kind of error (as far as i know, not an expert in bash semantics though), so it wouldnt be quite correct to exit with 1 (or other number)

¯\_(ツ)_/¯ an error code for what's not technically an error, yeah, but it'd do the trick for a wee script like this I think.

[Andarist]

So I've created https://github.com/Andarist/npm-self-link as a simple tool to help with that task (I need to reuse it in 2 other macros). I've amended this PR to use it and I've invited u to collaboration on the tool (both on github & npm)

I see that you run your tests on node@6 too and I've used async/await syntax in the tool - gonna add a transpilation step some time later today to account for node@6.

[haltcase]

@Andarist sounds good! node 6 EoLs in April so I'd want to support it until then.

[Andarist]

After a serious of fast broken releases 😅 I've added node@6 support to npm-self-link. Tests are passing here 😉

[haltcase]

Thanks @Andarist!