refactor: middle ware triggers

src/samples/slay-the-spire-like/system/utils/middleware.ts

@@ -0,0 +1,34 @@
+type Middleware<TContext, TReturn> = (
+  context: TContext,
+  next: () => Promise<TReturn>
+) => Promise<TReturn>;
+
+export type MiddlewareChain<TContext, TReturn> = {
+  use: (middleware: Middleware<TContext, TReturn>) => void;
+  execute: (context: TContext) => Promise<TReturn>;
+};
+
+export function createMiddlewareChain<TContext extends object, TReturn=TContext>(
+  fallback?: (context: TContext) => Promise<TReturn>
+): MiddlewareChain<TContext, TReturn> {
+  const middlewares: Middleware<TContext, TReturn>[] = [];
+
+  return {
+    use(middleware: Middleware<TContext, TReturn>) {
+      middlewares.push(middleware);
+    },
+    async execute(context: TContext) {
+      let index = 0;
+
+      async function dispatch(ctx: TContext): Promise<TReturn> {
+        if (index >= middlewares.length) {
+          return fallback ? fallback(ctx) : ctx as unknown as TReturn;
+        }
+        const current = middlewares[index++];
+        return current(ctx, () => dispatch(ctx));
+      }
+
+      return dispatch(context);
+    },
+  };
+}