Update module loader to work with aot compilation

Author: sis0k0

Diff for: nativescript-angular/router/ns-module-factory-loader.ts

@@ -5,8 +5,9 @@ import {
     NgModuleFactoryLoader
 } from "@angular/core";
 
-import * as fs from "file-system";
+import { path, knownFolders } from "file-system";
 
+declare var System: any;
 const SEPARATOR = "#";
 const FACTORY_CLASS_SUFFIX = "NgFactory";
 const FACTORY_PATH_SUFFIX = ".ngfactory";
@@ -20,33 +21,62 @@ export class NsModuleFactoryLoader implements NgModuleFactoryLoader {
     }
 
     load(path: string): Promise<NgModuleFactory<any>> {
-        let [modulePath, exportName] = path.split(SEPARATOR);
-
-        if (typeof exportName === "undefined") {
-            exportName = "default";
-        }
+        let {modulePath, exportName} = this.splitPath(path);
 
         if (this.offlineMode) {
-            modulePath = factoryModulePath(modulePath);
-            exportName = factoryExportName(exportName);
-        }
-        else {
-            modulePath = fs.path.normalize(fs.path.join(fs.knownFolders.currentApp().path, modulePath));
+            return this.loadFactory(modulePath, exportName);
+        } else {
+            return this.loadAndCompile(modulePath, exportName);
         }
+    }
+
+    private loadFactory(modulePath: string, exportName: string): Promise<NgModuleFactory<any>> {
+        modulePath = factoryModulePath(modulePath);
+        exportName = factoryExportName(exportName);
+
+        return System.import(modulePath)
+            .then((module: any) => module[exportName])
+            .then((factory: any) => checkNotEmpty(factory, modulePath, exportName));
+    }
+
+    private loadAndCompile(modulePath: string, exportName: string): Promise<NgModuleFactory<any>> {
+        modulePath = getAbsolutePath(modulePath);
 
         let loadedModule = require(modulePath)[exportName];
-        if (!loadedModule) {
-            throw new Error(`Cannot find "${exportName}" in "${modulePath}"`);
+        checkNotEmpty(loadedModule, modulePath, exportName);
+
+        return Promise.resolve(this.compiler.compileModuleAsync(loadedModule));
+    }
+
+    private splitPath(path: string): {modulePath: string, exportName: string} {
+        let [modulePath, exportName] = path.split(SEPARATOR);
+
+        if (typeof exportName === "undefined") {
+            exportName = "default";
         }
 
-        return this.offlineMode ? Promise.resolve(loadedModule) : this.compiler.compileModuleAsync(loadedModule);
+        return {modulePath, exportName};
     }
 }
 
+function getAbsolutePath(relativePath: string) {
+    return path.normalize(path.join(knownFolders.currentApp().path, relativePath));
+}
+
 function factoryModulePath(modulePath) {
     return `${modulePath}${FACTORY_PATH_SUFFIX}`;
 }
 
 function factoryExportName(exportName) {
-    return exportName === "default" ? exportName : `${exportName}${FACTORY_CLASS_SUFFIX}`;
-}
+    return exportName === "default" ?
+        exportName :
+        `${exportName}${FACTORY_CLASS_SUFFIX}`;
+}
+
+function checkNotEmpty(value: any, modulePath: string, exportName: string): any {
+    if (!value) {
+        throw new Error(`Cannot find '${exportName}' in '${modulePath}'`);
+    }
+
+    return value;
+}