Add web front-end and fix API issues

node_modules/concurrently/dist/lib/flow-control/output-error-handler.js

@@ -0,0 +1,23 @@
+import { fromSharedEvent } from '../observables.js';
+/**
+ * Kills processes and aborts further command spawning on output stream error (namely, SIGPIPE).
+ */
+export class OutputErrorHandler {
+    outputStream;
+    abortController;
+    constructor({ abortController, outputStream, }) {
+        this.abortController = abortController;
+        this.outputStream = outputStream;
+    }
+    handle(commands) {
+        const subscription = fromSharedEvent(this.outputStream, 'error').subscribe(() => {
+            commands.forEach((command) => command.kill());
+            // Avoid further commands from spawning, e.g. if `RestartProcess` is used.
+            this.abortController.abort();
+        });
+        return {
+            commands,
+            onFinish: () => subscription.unsubscribe(),
+        };
+    }
+}