feat: version 2 beta

libraries/aggregate-factory.ts

@@ -0,0 +1,74 @@
+import { AggregateRootClass } from "./aggregate.ts";
+import { EventFactory } from "./event-factory.ts";
+import { AnyEventStore } from "./event-store.ts";
+
+/**
+ * Indexes a list of event factories for use with aggregates and event stores
+ * when generating or accessing event functionality.
+ *
+ * @example
+ *
+ * ```ts
+ * import { AggregateRoot, AggregateFactory } from "@valkyr/event-store";
+ * import z from "zod";
+ *
+ * class User extends AggregateRoot {}
+ *
+ * const factory = new AggregateFactory([User]);
+ *
+ * export type Aggregates = typeof factory.$aggregates;
+ * ```
+ */
+export class AggregateFactory<
+  const TEventFactory extends EventFactory = EventFactory,
+  const TAggregates extends AggregateRootClass<TEventFactory>[] = AggregateRootClass<TEventFactory>[],
+> {
+  /**
+   * Optimized aggregate lookup index.
+   */
+  readonly #index = new Map<TAggregates[number]["name"], TAggregates[number]>();
+
+  aggregates: TAggregates;
+
+  /**
+   * Inferred type of the aggregates registered with the factory.
+   */
+  declare readonly $aggregates: TAggregates;
+
+  /**
+   * Instantiate a new AggregateFactory with given list of supported aggregates.
+   *
+   * @param aggregates - Aggregates to register with the factory.
+   */
+  constructor(aggregates: TAggregates) {
+    this.aggregates = aggregates;
+    for (const aggregate of aggregates) {
+      this.#index.set(aggregate.name, aggregate);
+    }
+  }
+
+  /**
+   * Attaches the given store to all the aggregates registered with this instance.
+   *
+   * If the factory is passed into multiple event stores, the aggregates will be
+   * overriden by the last execution. Its recommended to create individual instances
+   * for each list of aggregates.
+   *
+   * @param store - Event store to attach to the aggregates.
+   */
+  withStore(store: AnyEventStore): this {
+    for (const aggregate of this.aggregates) {
+      aggregate.$store = store;
+    }
+    return this;
+  }
+
+  /**
+   * Get a registered aggregate from the factory.
+   *
+   * @param name - Aggregate to retrieve.
+   */
+  get<TName extends TAggregates[number]["name"]>(name: TName): Extract<TAggregates[number], { name: TName }> {
+    return this.#index.get(name) as Extract<TAggregates[number], { name: TName }>;
+  }
+}