Allow to consume with C++ sources to build as part of npm install

[bpasero]

I think ever since 062bca4, components that depend on @parcel/watcher no longer compile the module from its C++ sources but get prebuild versions.

In VS Code we require to build C++ modules from sources, so it would be great to have the ability back to do so, so that we can move to newer versions of this module.

I think a starting point is to have the sources back in the NPM package: #157

Alternatively, maybe a different NPM package could be published that is strictly for building from sources?

//cc @devongovett

[devongovett]

We may be able to publish the source files. The thing I'd be worried about and need to look into is whether including the binding.gyp causes npm to always build from source rather than using the prebuilds, and if there is a way to avoid that.

[deepak1556]

Hi! I believe npm will build following the default install script logic since this package does not override one since #144. An idea could be to override the install script section with a simple script that checks if process.env.npm_config_build_from_source set and proceeds to run node-gyp rebuild command otherwise do nothing.

[tmm1]

What's the simplest cross-platform solution for conditional npm script?

"install":"node -e \"if (process.env.npm_config_build_from_source) require('child_process')...

[deepak1556]

You can take https://github.com/prebuild/node-gyp-build/blob/master/bin.js as an example. Basically what we want is,

if (buildFromSource()) {
  build()
}

[deepak1556]

Thanks @devongovett 🚀