feat(frontend): XState statecharts

Expressing logic in statecharts for complex stateful behaviours should
improve maintainability

We use @xstate/cli to statically analyze statcharts before typechecking

2 files changed, 2 insertions, 35 deletions

diff --git a/subprojects/frontend/src/utils/CancelledError.ts b/subprojects/frontend/src/utils/CancelledError.ts
index 8d3e55d8..ee23676f 100644
--- a/subprojects/frontend/src/utils/CancelledError.ts
+++ b/subprojects/frontend/src/utils/CancelledError.ts
@@ -1,5 +1,5 @@
 export default class CancelledError extends Error {
-  constructor() {
-    super('Operation cancelled');
+  constructor(message = 'Operation cancelled') {
+    super(message);
   }
 }
diff --git a/subprojects/frontend/src/utils/Timer.ts b/subprojects/frontend/src/utils/Timer.ts
deleted file mode 100644
index 4bb1bb9c..00000000
--- a/subprojects/frontend/src/utils/Timer.ts
+++ /dev/null
@@ -1,33 +0,0 @@
-export default class Timer {
-  private readonly callback: () => void;
-
-  private readonly defaultTimeout: number;
-
-  private timeout: number | undefined;
-
-  constructor(callback: () => void, defaultTimeout = 0) {
-    this.callback = () => {
-      this.timeout = undefined;
-      callback();
-    };
-    this.defaultTimeout = defaultTimeout;
-  }
-
-  schedule(timeout?: number | undefined): void {
-    if (this.timeout === undefined) {
-      this.timeout = setTimeout(this.callback, timeout ?? this.defaultTimeout);
-    }
-  }
-
-  reschedule(timeout?: number | undefined): void {
-    this.cancel();
-    this.schedule(timeout);
-  }
-
-  cancel(): void {
-    if (this.timeout !== undefined) {
-      clearTimeout(this.timeout);
-      this.timeout = undefined;
-    }
-  }
-}