Custom ResourceLoader support

[fstanis]

JSDom supports a custom resource loader, e.g:

class CustomResourceLoader extends jsdom.ResourceLoader {
  fetch(url, options) {
    console.log(`Loading ${url}...`);
    return super.fetch(url, options);
  }
}

const dom = new JSDOM(``, { resources: new CustomResourceLoader() });

However, window (and browser-env) doesn't allow this because it overrides the resources field:

window/src/index.js

Lines 8 to 12 in 82c7830

	const resources = new ResourceLoader({
	proxy,
	strictSSL,
	userAgent
	});

Any chance this could be changed so that a custom loader is allowed?

[lukechilds]

Sure, I'd happily accept a PR for this as long as it doesn't break existing behaviour.

[fstanis]

Sure, #37 does this.

It feels a bit clunky, I think the best option would be to just forward the whole jsdomConfig, i.e.

module.exports = class Window {
	constructor(jsdomConfig = {}) {
		return (new JSDOM('', jsdomConfig)).window;
	}
};

But I'm assuming there's some context I'm missing and also this would break backwards compatibility.