From f7c1f1e716c855c3e8725cb5acd4ea124a841713 Mon Sep 17 00:00:00 2001
From: liujuping <liujup@foxmail.com>
Date: Wed, 16 Aug 2023 11:34:56 +0800
Subject: [PATCH] feat(event): add event.prependListener api

---
 docs/docs/api/event.md                | 13 +++++++++++++
 packages/editor-core/src/event-bus.ts |  8 ++++++++
 packages/shell/src/api/event.ts       | 14 ++++++++++++++
 packages/types/src/shell/api/event.ts |  7 +++++++
 4 files changed, 42 insertions(+)

diff --git a/docs/docs/api/event.md b/docs/docs/api/event.md
index 9e2bdf641..0919b41fd 100644
--- a/docs/docs/api/event.md
+++ b/docs/docs/api/event.md
@@ -25,6 +25,19 @@ on(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable;
 ```
 相关类型：[IPublicTypeDisposable](https://github.com/alibaba/lowcode-engine/blob/main/packages/types/src/shell/type/disposable.ts)
 
+### prependListener
+监听事件，会在其他回调函数之前执行
+
+```typescript
+/**
+ * 监听事件，会在其他回调函数之前执行
+ * @param event 事件名称
+ * @param listener 事件回调
+ */
+prependListener(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable;
+```
+相关类型：[IPublicTypeDisposable](https://github.com/alibaba/lowcode-engine/blob/main/packages/types/src/shell/type/disposable.ts)
+
 ### off
 取消监听事件
 
diff --git a/packages/editor-core/src/event-bus.ts b/packages/editor-core/src/event-bus.ts
index 95f26f77e..ae9d28905 100644
--- a/packages/editor-core/src/event-bus.ts
+++ b/packages/editor-core/src/event-bus.ts
@@ -55,6 +55,14 @@ export class EventBus implements IEventBus {
     };
   }
 
+  prependListener(event: string, listener: (...args: any[]) => void): () => void {
+    this.eventEmitter.prependListener(event, listener);
+    this.getLogger().debug(`${this.getMsgPrefix('prependListener')} ${event}`);
+    return () => {
+      this.off(event, listener);
+    };
+  }
+
   /**
    * 取消监听事件
    * @param event 事件名称
diff --git a/packages/shell/src/api/event.ts b/packages/shell/src/api/event.ts
index 0fb41966e..f2adca98c 100644
--- a/packages/shell/src/api/event.ts
+++ b/packages/shell/src/api/event.ts
@@ -36,6 +36,20 @@ export class Event implements IPublicApiEvent {
     }
   }
 
+  /**
+   * 监听事件，会在其他回调函数之前执行
+   * @param event 事件名称
+   * @param listener 事件回调
+   */
+  prependListener(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable {
+    if (isPluginEventName(event)) {
+      return this[eventBusSymbol].prependListener(event, listener);
+    } else {
+      logger.warn(`fail to prependListener event ${event}, event should have a prefix like 'somePrefix:eventName'`);
+      return () => {};
+    }
+  }
+
   /**
    * 取消监听事件
    * @param event 事件名称
diff --git a/packages/types/src/shell/api/event.ts b/packages/types/src/shell/api/event.ts
index 02b8bc5b3..5b8c59e13 100644
--- a/packages/types/src/shell/api/event.ts
+++ b/packages/types/src/shell/api/event.ts
@@ -10,6 +10,13 @@ export interface IPublicApiEvent {
    */
   on(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable;
 
+  /**
+   * 监听事件，会在其他回调函数之前执行
+   * add monitor to a event
+   * @param event 事件名称
+   * @param listener 事件回调
+   */
+  prependListener(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable;
 
   /**
    * 取消监听事件