src/vs/workbench/api/worker/extHostExtensionService.ts/WorkerRequireInterceptor/getModule
class WorkerRequireInterceptor:	getModule(request: string, parent: URI): undefined | any {
		for (let alternativeModuleName of this._alternatives) {
			let alternative = alternativeModuleName(request);
			if (alternative) {
				request = alternative;
				break;
			}
		}

		if (this._factories.has(request)) {
			return this._factories.get(request)!.load(request, parent, () => { throw new Error('CANNOT LOAD MODULE from here.'); });
		}
		return undefined;
	}