refactor(core): Consolidate Subscription type and remove Base interface

Replaced Sub type alias with Subscription and merged its properties into Subscription interface. Removed the unnecessary Base interface, simplifying the codebase and reducing redundancy.

Signed-off-by: Alberto Ricart <alberto@synadia.com>

core/src/core.ts

@@ -359,11 +359,6 @@ export interface ServersChanged {
   readonly deleted: string[];
 }
 
-/**
- * Type alias for NATS core subscriptions
- */
-export type Subscription = Sub<Msg>;
-
 export enum Match {
   // Exact option is case sensitive
   Exact = 0,
@@ -696,7 +691,7 @@ export function syncIterator<T>(src: AsyncIterable<T>): SyncIterator<T> {
 /**
  * Basic interface to a Subscription type
  */
-export interface Sub<T> extends AsyncIterable<T> {
+export interface Subscription extends AsyncIterable<Msg> {
   /** A promise that resolves when the subscription closes */
   closed: Promise<void>;
 
@@ -729,7 +724,7 @@ export interface Sub<T> extends AsyncIterable<T> {
   /**
    * @ignore
    */
-  callback(err: NatsError | null, msg: Msg): void;
+  callback: MsgCallback<Msg>;
 
   /**
    * Returns the subject that was used to create the subscription.
@@ -1088,15 +1083,6 @@ export const DEFAULT_HOST = "127.0.0.1";
 
 export type ConnectFn = (opts: ConnectionOptions) => Promise<NatsConnection>;
 
-export interface Base {
-  subject: string;
-  callback: (error: NatsError | null, msg: Msg) => void;
-  received: number;
-  timeout?: number | null;
-  max?: number | undefined;
-  draining: boolean;
-}
-
 export interface URLParseFn {
   (u: string, encrypted?: boolean): string;
 }

core/src/internal_mod.ts

@@ -108,7 +108,6 @@ export type {
   ServersChanged,
   Stats,
   Status,
-  Sub,
   SubOpts,
   Subscription,
   SubscriptionOptions,

core/src/mod.ts

@@ -76,7 +76,6 @@ export type {
   ServersChanged,
   Stats,
   Status,
-  Sub,
   SubOpts,
   Subscription,
   SubscriptionOptions,

core/src/protocol.ts

@@ -32,7 +32,6 @@ import { Features, parseSemVer } from "./semver.ts";
 import { DebugEvents, ErrorCode, Events, NatsError } from "./core.ts";
 
 import type {
-  Base,
   ConnectionOptions,
   Dispatcher,
   Msg,
@@ -101,7 +100,7 @@ export class Connect {
 }
 
 export class SubscriptionImpl extends QueuedIteratorImpl<Msg>
-  implements Base, Subscription {
+  implements Subscription {
   sid!: number;
   queue?: string;
   draining: boolean;

services/src/service.ts

@@ -32,7 +32,7 @@ import type {
   PublishOptions,
   QueuedIterator,
   ReviverFn,
-  Sub,
+  Subscription,
 } from "@nats-io/nats-core/internal";
 
 import {
@@ -239,7 +239,7 @@ type ServiceSubscription<T = unknown> =
   & NamedEndpoint
   & {
     internal: boolean;
-    sub: Sub<T>;
+    sub: Subscription;
     qi?: QueuedIterator<T>;
     stats: NamedEndpointStatsImpl;
     metadata?: Record<string, string>;