fix(server): event handler bindings (#10165)

packages/backend/server/src/base/nestjs/decorator.ts

@@ -0,0 +1,45 @@
+export function makeMethodDecorator<
+  T extends any[],
+  Fn extends (...args: any[]) => any,
+>(
+  decorator: (...args: T) => (target: any, key: string | symbol, fn: Fn) => Fn
+) {
+  return (...args: T) => {
+    return (
+      target: any,
+      key: string | symbol,
+      desc: TypedPropertyDescriptor<any>
+    ) => {
+      const originalFn = desc.value;
+      if (!originalFn || typeof originalFn !== 'function') {
+        throw new Error(
+          `MethodDecorator must be applied to a function but got ${typeof originalFn}`
+        );
+      }
+
+      const decoratedFn = decorator(...args)(target, key, originalFn);
+      desc.value = decoratedFn;
+      return desc;
+    };
+  };
+}
+
+export function PushMetadata<T>(key: string | symbol, value: T) {
+  const decorator: ClassDecorator | MethodDecorator = (
+    target,
+    _,
+    descriptor
+  ) => {
+    const metadataTarget = descriptor?.value ?? target;
+
+    const metadataArray = Reflect.getMetadata(key, metadataTarget) || [];
+    metadataArray.push(value);
+    Reflect.defineMetadata(key, metadataArray, metadataTarget);
+  };
+
+  return decorator;
+}
+
+export function sliceMetadata<T>(key: string | symbol, target: any): T[] {
+  return Reflect.getMetadata(key, target) || [];
+}

packages/backend/server/src/base/nestjs/index.ts

@@ -1,3 +1,4 @@
 import './config';
+export * from './decorator';
 export * from './exception';
 export * from './optional-module';