some small unix signal handler clarification

Author: sezanzeb

backend/src/services/unix-signal-service.ts

@@ -52,20 +52,25 @@ export class UnixSignalService implements IUnixSignalService {
 
   /**
    * Registers the given handler to execute for the given signal.
-   * @param signal The signal to register
+   * @param signal The signal to register, for example SIGINT
    * @param handler The handler to use for the signal
    */
   public async registerSignalHandler(
     signal: NodeJS.Signals,
     handler: ISignalHandler,
   ): Promise<void> {
     if (!this._handlers.has(signal)) {
-      this._handlers.set(signal, [() => {
-        // TODO I don't know why
-        console.error("process.exit", signal, handler)
+      // Ensure an erray with the default handler exists, to which more
+      // handlers can be added
+      const defaultHandler = () => {
+        console.error(`Received signal ${signal}, exiting`)
         process.exit()
-      }]);
+      }
+
+      this._handlers.set(signal, [defaultHandler]);
 
+      // Ensure all added handlers in the array are called, when the signal event
+      // happens
       process.on(signal, () => this.handleSignal(signal));
     }