feat: CancelableTask&Fallback

src/common/fall-back.ts

@@ -0,0 +1,26 @@
+type Handler<T> = () => T | Promise<T>;
+
+export class Fallback<T> {
+    private handlers: Handler<T>[] = [];
+
+    add(handler: Handler<T>): this {
+        this.handlers.push(handler);
+        return this;
+    }
+
+    // 执行处理程序链
+    async run(): Promise<T> {
+        const errors: Error[] = [];
+        for (const handler of this.handlers) {
+            try {
+                const result = await handler();
+                if (result !== undefined) {
+                    return result;
+                }
+            } catch (error) {
+                errors.push(error instanceof Error ? error : new Error(String(error)));
+            }
+        }
+        throw new AggregateError(errors, 'All handlers failed');
+    }
+}