feat(util): system.js ng-module loader

system.js ng-module loader

Author: danbucholtz

src/util/module-loader.ts

@@ -0,0 +1,49 @@
+import { ComponentFactoryResolver, Injectable, Injector, OpaqueToken, Type } from '@angular/core';
+import { NgModuleLoader } from './ng-module-loader';
+
+export const LAZY_LOADED_TOKEN = new OpaqueToken('LZYCMP');
+
+/**
+ * @private
+ */
+@Injectable()
+export class ModuleLoader {
+
+  constructor(
+    private _ngModuleLoader: NgModuleLoader,
+    private _injector: Injector) {}
+
+
+  load(modulePath: string): Promise<LoadedModule> {
+    console.time(`ModuleLoader, load: ${modulePath}'`);
+
+    const splitString = modulePath.split(SPLITTER);
+
+    return this._ngModuleLoader.load(splitString[0], splitString[1])
+      .then(loadedModule => {
+        console.timeEnd(`ModuleLoader, load: ${modulePath}'`);
+        const ref = loadedModule.create(this._injector);
+
+        return {
+          componentFactoryResolver: ref.componentFactoryResolver,
+          component: ref.injector.get(LAZY_LOADED_TOKEN)
+        };
+      });
+  }
+}
+
+const SPLITTER = '#';
+
+
+/**
+ * @private
+ */
+export function provideModuleLoader(ngModuleLoader: NgModuleLoader, injector: Injector) {
+  return new ModuleLoader(ngModuleLoader, injector);
+}
+
+
+export interface LoadedModule {
+  componentFactoryResolver: ComponentFactoryResolver;
+  component: Type<any>;
+};

src/util/ng-module-loader.ts

@@ -0,0 +1,77 @@
+import { Compiler, Injectable, NgModuleFactory, Optional } from '@angular/core';
+
+const FACTORY_CLASS_SUFFIX = 'NgFactory';
+
+/**
+ * Configuration for NgModuleLoader.
+ * token.
+ *
+ * @experimental
+ */
+export abstract class NgModuleLoaderConfig {
+  /**
+   * Prefix to add when computing the name of the factory module for a given module name.
+   */
+  factoryPathPrefix: string;
+
+  /**
+   * Suffix to add when computing the name of the factory module for a given module name.
+   */
+  factoryPathSuffix: string;
+}
+
+const DEFAULT_CONFIG: NgModuleLoaderConfig = {
+  factoryPathPrefix: '',
+  factoryPathSuffix: '.ngfactory',
+};
+
+/**
+ * NgModuleFactoryLoader that uses SystemJS to load NgModuleFactory
+ */
+@Injectable()
+export class NgModuleLoader {
+  private _config: NgModuleLoaderConfig;
+
+  constructor(private _compiler: Compiler, @Optional() config?: NgModuleLoaderConfig) {
+    this._config = config || DEFAULT_CONFIG;
+  }
+
+  load(modulePath: string, ngModuleExport: string) {
+    const offlineMode = this._compiler instanceof Compiler;
+    return offlineMode ? loadPrecompiledFactory(this._config, modulePath, ngModuleExport) : loadAndCompile(this._compiler, modulePath, ngModuleExport);
+  }
+}
+
+
+function loadAndCompile(compiler: Compiler, modulePath: string, ngModuleExport: string): Promise<NgModuleFactory<any>> {
+  if (!ngModuleExport) {
+    ngModuleExport = 'default';
+  }
+
+  return System.import(modulePath)
+    .then((rawModule: any) => {
+      const module = rawModule[ngModuleExport];
+      if (!module) {
+        throw new Error(`Module ${modulePath} does not export ${ngModuleExport}`);
+      }
+      return compiler.compileModuleAsync(module);
+    });
+}
+
+
+function loadPrecompiledFactory(config: NgModuleLoaderConfig, modulePath: string, ngModuleExport: string): Promise<NgModuleFactory<any>> {
+  let factoryClassSuffix = FACTORY_CLASS_SUFFIX;
+  if (ngModuleExport === undefined) {
+    ngModuleExport = 'default';
+    factoryClassSuffix = '';
+  }
+
+  return System.import(config.factoryPathPrefix + modulePath + config.factoryPathSuffix)
+    .then((rawModule: any) => {
+      const ngModuleFactory = rawModule[ngModuleExport + factoryClassSuffix];
+      if (!ngModuleFactory) {
+        throw new Error(`Module ${modulePath} does not export ${ngModuleExport}`);
+      }
+      return ngModuleFactory;
+    });
+}