reusable extensibility lib (#585)

reusable extensibility lib (part 1)

docs/extending.md

@@ -1119,51 +1119,44 @@ As with other content actions, custom plugins can disable, update or extend `Ope
 You can use `ExtensionService` to register custom components, authentication guards,
 rule evaluators, etc.
 
-It is recommended to register custom content during application startup
-by utilising the `APP_INITIALIZER` injection token that comes with Angular.
+It is recommended to register custom content from within the module constructor.
 In that case all plugins will be available right after main application component is ready.
 
 Update the main application module `app.module.ts`, or create your own module,
 and use the following snippet to register custom content:
 
 ```typescript
-export function setupExtensions(extensions: ExtensionService): Function {
-    return () =>
-        new Promise(resolve => {
-
-            extensions.setComponents({
-                'plugin1.components.my': MyComponent1,
-                'plugin1.layouts.my': MyLayout
-            });
-
-            extensions.setAuthGuards({
-                'plugin.auth': MyAuthGuard
-            });
-
-            extensions.setEvaluators({
-                'plugin1.rules.custom1': MyCustom1Evaluator,
-                'plugin1.rules.custom2': MyCustom2Evaluator
-            });
-
-            resolve(true);
-        });
-}
+import { ExtensionsModule, ExtensionService } from '@alfresco/adf-extensions';
 
 @NgModule({
+    imports: [ ExtensionsModule.forChild() ]
     declarations: [ MyComponent1, MyLayout ],
-    entryComponents: [ MyComponent1, MyLayout ],
-    providers: [
-        {
-            provide: APP_INITIALIZER,
-            useFactory: setupExtensions,
-            deps: [ ExtensionService ],
-            multi: true
-        }
-    ]
+    entryComponents: [ MyComponent1, MyLayout ]
 })
-export class MyExtensionModule {}
+export class MyExtensionModule {
+
+    constructor(extensions: ExtensionService) {
+        extensions.setComponents({
+            'plugin1.components.my': MyComponent1,
+            'plugin1.layouts.my': MyLayout
+        });
+
+        extensions.setAuthGuards({
+            'plugin.auth': MyAuthGuard
+        });
+
+        extensions.setEvaluators({
+            'plugin1.rules.custom1': MyCustom1Evaluator,
+            'plugin1.rules.custom2': MyCustom2Evaluator
+        });
+    }
+
+}
 ```
 
+Use `ExtensionsModule.forChild()` when importing into the child modules,
+and `ExtensionsModule.forRoot()` for the main application module.
+
 <p class="warning">
 According to Angular rules, all components that are created dynamically at runtime
 need to be registered within the `entryComponents` section of the NgModule.