Initial commit with CC BY-NC-ND 4.0 license

SL/bus/chain/Chain.js

@@ -0,0 +1,56 @@
+/**
+ * 通用责任链/中间件管理器
+ * 用于规范操作顺序，支持异步流程控制
+ */
+export class Chain {
+    constructor() {
+        this.middlewares = [];
+    }
+
+    /**
+     * 注册中间件
+     * @param {Function} fn (context, next) => Promise<void> | void
+     */
+    use(fn) {
+        if (typeof fn !== 'function') {
+            throw new Error('[Chain] Middleware must be a function');
+        }
+        this.middlewares.push(fn);
+        return this;
+    }
+
+    /**
+     * 执行责任链
+     * @param {Object} context 传递给中间件的上下文对象
+     */
+    async execute(context = {}) {
+        let index = -1;
+        
+        const dispatch = async (i) => {
+            if (i <= index) {
+                throw new Error('[Chain] next() called multiple times in one middleware');
+            }
+            index = i;
+            
+            const fn = this.middlewares[i];
+            if (!fn) return; // 链结束
+
+            try {
+                // 执行中间件，传入 context 和 next 函数
+                await fn(context, () => dispatch(i + 1));
+            } catch (err) {
+                console.error('[Chain] Middleware execution error:', err);
+                throw err;
+            }
+        };
+
+        await dispatch(0);
+    }
+
+    /**
+     * 清空链
+     */
+    clear() {
+        this.middlewares = [];
+    }
+}