feat: add close() method to ServerSentEventGenerator

src/abstractServerSentEventGenerator.ts

@@ -85,6 +85,16 @@ export abstract class ServerSentEventGenerator<T = string[]> {
     );
   }
 
+  /**
+   * Closes the server-sent event stream.
+   *
+   * Use this method to manually close the stream when `keepalive: true` is set.
+   * This is required when you want to close the stream before the client disconnects.
+   *
+   * Concrete implementations must override this method to close the underlying stream.
+   */
+  public abstract close(): void;
+
   private eachNewlineIsADataLine(prefix: string, data: string) {
     return data.split("\n").map((line) => {
       return `${prefix} ${line}`;

src/node/serverSentEventGenerator.ts

@@ -94,6 +94,15 @@ export class ServerSentEventGenerator extends AbstractSSEGenerator {
     return eventLines;
   }
 
+  /**
+   * Closes the server-sent event stream.
+   *
+   * Ends the Node.js response stream.
+   */
+  public override close(): void {
+    this.res.end();
+  }
+
   /**
    * Reads client sent signals based on HTTP methods
    *

src/web/serverSentEventGenerator.ts

@@ -103,6 +103,31 @@ export class ServerSentEventGenerator extends AbstractSSEGenerator {
     return eventLines;
   }
 
+  /**
+   * Closes the server-sent event stream.
+   *
+   * Closes the ReadableStream controller.
+   */
+  public override close(): void {
+    if (!this.controller) {
+      return;
+    }
+
+    try {
+      this.controller.close();
+    } catch (err) {
+      // ReadableStream controllers throw when already closed.
+      // We only ignore TypeError (which indicates the stream is already closed).
+      // Other errors should bubble up as they indicate real problems.
+      if (err instanceof TypeError) {
+        // Stream is already closed, which is fine - ignore
+        return;
+      }
+      // Re-throw unexpected errors
+      throw err;
+    }
+  }
+
   /**
    * Reads client sent signals based on HTTP methods
    *