Add push$ to Collection; make Container listen for retroactive blueprint changes

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@extollo/lib",
-  "version": "0.14.2",
+  "version": "0.14.3",
   "description": "The framework library that lifts up your code.",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",

src/di/Container.ts

@@ -14,7 +14,7 @@ import {
     Collection,
     globalRegistry,
     hasOwnProperty,
-    logIfDebugging,
+    logIfDebugging, Unsubscribe,
 } from '../util'
 import {ErrorWithContext, withErrorContext} from '../util/error/ErrorWithContext'
 import {Factory} from './factory/Factory'
@@ -100,6 +100,8 @@ export class Container {
                     .then(value => listener.callback(value))
             })
 
+        container.subscribeToBlueprintChanges(ContainerBlueprint.getContainerBlueprint())
+
         return container
     }
 
@@ -153,11 +155,33 @@ export class Container {
      */
     protected waitingLifecycleCallbacks: Collection<WeakRef<AwareOfContainerLifecycle>> = new Collection()
 
+    /**
+     * Collection of subscriptions to ContainerBlueprint events.
+     * We keep this around so we can remove the subscriptions when the container is destroyed.
+     * @protected
+     */
+    protected blueprintSubscribers: Collection<Unsubscribe> = new Collection()
+
     constructor() {
         this.registerSingletonInstance<Container>(Container, this)
         this.registerSingleton('injector', this)
     }
 
+    /** Make the container listen to changes in the given blueprint. */
+    private subscribeToBlueprintChanges(blueprint: ContainerBlueprint): void {
+        this.blueprintSubscribers.push(
+            blueprint.resolve$(factory => this.registerFactory(factory())),
+        )
+
+        this.blueprintSubscribers.push(
+            blueprint.resolveConstructable$(factoryClass => this.registerFactory(this.make(factoryClass))),
+        )
+
+        this.blueprintSubscribers.push(
+            blueprint.resolveResolutionCallbacks$(listener => this.onResolve(listener.key).then(value => listener.callback(value))),
+        )
+    }
+
     /**
      * Purge all factories and instances of the given key from this container.
      * @param key
@@ -622,6 +646,8 @@ export class Container {
      * Perform any cleanup necessary to destroy this container instance.
      */
     destroy(): void {
+        this.blueprintSubscribers.mapCall('unsubscribe')
+
         this.waitingLifecycleCallbacks
             .mapCall('deref')
             .whereDefined()

src/di/ContainerBlueprint.ts

@@ -3,6 +3,8 @@ import NamedFactory from './factory/NamedFactory'
 import {AbstractFactory} from './factory/AbstractFactory'
 import {Factory} from './factory/Factory'
 import {ClosureFactory} from './factory/ClosureFactory'
+import {Collection, collect} from '../util/collection/Collection'
+import {Subscription, Unsubscribe} from '../util/support/BehaviorSubject'
 
 /** Simple type alias for a callback to a container's onResolve method. */
 export type ContainerResolutionCallback<T> = (() => unknown) | ((t: T) => unknown)
@@ -25,11 +27,11 @@ export class ContainerBlueprint {
         return this.instance
     }
 
-    protected factories: (() => AbstractFactory<any>)[] = []
+    protected factories: Collection<(() => AbstractFactory<any>)> = collect()
 
-    protected constructableFactories: StaticClass<AbstractFactory<any>, any>[] = []
+    protected constructableFactories: Collection<StaticClass<AbstractFactory<any>, any>> = collect()
 
-    protected resolutionCallbacks: ({key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>})[] = []
+    protected resolutionCallbacks: Collection<{key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>}> = collect()
 
     /**
      * Register some factory class with the container. Should take no construction params.
@@ -74,7 +76,16 @@ export class ContainerBlueprint {
      * Get an array of factory instances in the blueprint.
      */
     resolve(): AbstractFactory<any>[] {
-        return this.factories.map(x => x())
+        return this.factories.map(x => x()).all()
+    }
+
+    /**
+     * Subscribe to new factories being registered.
+     * Used by `Container` implementations to listen for factories being registered after the container is realized.
+     * @param sub
+     */
+    resolve$(sub: Subscription<() => AbstractFactory<any>>): Unsubscribe {
+        return this.factories.push$(sub)
     }
 
     /**
@@ -94,14 +105,32 @@ export class ContainerBlueprint {
      * Get an array of static Factory classes that need to be instantiated by
      * the container itself.
      */
-    resolveConstructable(): StaticClass<AbstractFactory<any>, any> {
-        return [...this.constructableFactories]
+    resolveConstructable(): StaticClass<AbstractFactory<any>, any>[] {
+        return this.constructableFactories.all()
+    }
+
+    /**
+     * Subscribe to new constructable factories being registered.
+     * Used by `Container` implementations to listen for factories registered after the container is realized.
+     * @param sub
+     */
+    resolveConstructable$(sub: Subscription<StaticClass<AbstractFactory<any>, any>>): Unsubscribe {
+        return this.constructableFactories.push$(sub)
     }
 
     /**
      * Get an array of DependencyKey-callback pairs to register with new containers.
      */
     resolveResolutionCallbacks(): ({key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>})[] {
-        return [...this.resolutionCallbacks]
+        return this.resolutionCallbacks.all()
+    }
+
+    /**
+     * Subscribe to new resolution callbacks being registered.
+     * Used by `Container` implementations to listen for callbacks registered after the container is realized.
+     * @param sub
+     */
+    resolveResolutionCallbacks$(sub: Subscription<{key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>}>): Unsubscribe {
+        return this.resolutionCallbacks.push$(sub)
     }
 }

src/di/decorator/injection.ts

@@ -166,6 +166,7 @@ export const Singleton = (name?: string): ClassDecorator => {
                 ...(name ? { name } : {}),
             }
 
+            logIfDebugging('extollo.di.singleton', 'Registering singleton target:', target, 'injectionType:', injectionType)
             Reflect.defineMetadata(DEPENDENCY_KEYS_SERVICE_TYPE_KEY, injectionType, target)
             Injectable()(target)
 

src/util/collection/Collection.ts

@@ -1,4 +1,5 @@
 import {AsyncPipe, Pipeline} from '../support/Pipe'
+import {Unsubscribe, Subscription} from '../support/BehaviorSubject'
 
 type CollectionItem<T> = T
 type MaybeCollectionItem<T> = CollectionItem<T> | undefined
@@ -50,6 +51,8 @@ export {
 class Collection<T> {
     private storedItems: CollectionItem<T>[] = []
 
+    private pushSubscribers: Subscription<T>[] = []
+
     /**
      * Create a new collection from an array of items.
      * @param items
@@ -966,6 +969,7 @@ class Collection<T> {
      */
     prepend(item: CollectionItem<T>): Collection<T> {
         this.storedItems = [item, ...this.storedItems]
+        this.callPushSubscribers(item)
         return this
     }
 
@@ -975,9 +979,33 @@ class Collection<T> {
      */
     push(item: CollectionItem<T>): Collection<T> {
         this.storedItems.push(item)
+        this.callPushSubscribers(item)
         return this
     }
 
+    /**
+     * Subscribe to listen for items being added to the collection.
+     * @param sub
+     */
+    push$(sub: Subscription<T>): Unsubscribe {
+        this.pushSubscribers.push(sub)
+        return {
+            unsubscribe: () => this.pushSubscribers = this.pushSubscribers.filter(x => x !== sub),
+        }
+    }
+
+    /** Helper to notify subscribers that an item has been pushed to the collection. */
+    private callPushSubscribers(item: T): void {
+        this.pushSubscribers
+            .forEach(sub => {
+                if ( typeof sub === 'object' ) {
+                    sub?.next?.(item)
+                } else {
+                    sub(item)
+                }
+            })
+    }
+
     /**
      * Push the given items to the end of this collection.
      * Unlike `merge()`, this mutates the current collection's items.
@@ -987,6 +1015,7 @@ class Collection<T> {
         const concats = items instanceof Collection ? items.all() : items
         for ( const item of concats ) {
             this.storedItems.push(item)
+            this.callPushSubscribers(item)
         }
         return this
     }