From c845797101e21a163ac403fc65eac6db069a16b1 Mon Sep 17 00:00:00 2001
From: JC Brand <jc@opkode.com>
Date: Fri, 6 Oct 2023 15:18:43 +0200
Subject: [PATCH] Fix `listenTo` for ElementView

---
 src/element.js      | 50 +++++++++++++++++++++++++++++++++++++++------
 src/eventemitter.js |  4 ++--
 src/listening.js    | 24 +++++++++++++++++++++-
 src/utils/events.js |  2 +-
 4 files changed, 70 insertions(+), 10 deletions(-)

diff --git a/src/element.js b/src/element.js
index 4b5115c..f06a876 100644
--- a/src/element.js
+++ b/src/element.js
@@ -6,27 +6,47 @@ import EventEmitter from './eventemitter.js';
 const delegateEventSplitter = /^(\S+)\s*(.*)$/;
 
 class ElementView extends HTMLElement {
+
+  /**
+   * @typedef {import('./model.js').Model} Model
+   * @typedef {import('./collection.js').Collection} Collection
+   * @typedef {Record.<string, any>} Options
+   *
+   * @callback EventCallback
+   * @param {any} event
+   * @param {Model} model
+   * @param {Collection} collection
+   * @param {Options} [options]
+   */
+
+  set events (events) {
+    this._declarativeEvents = events;
+  }
+
   get events() {
-    return {};
+    return this._declarativeEvents;
   }
 
   /**
-   * @param {Record<string, any>} options
+   * @param {Options} options
    */
-  constructor(options) {
+  constructor(options={}) {
     super();
 
+    this.emitter = new EventEmitter();
+
     // Will be assigned to from Events
     this.stopListening = null;
 
     // Creating a View creates its initial element outside of the DOM,
     // if an existing element is not provided...
     this.cid = uniqueId('view');
+    this._declarativeEvents = {};
     this._domEvents = [];
 
     const { model, collection, events } = options;
 
-    Object.assign(this, { model, collection, events });
+    Object.assign(this, { model: model, collection, events });
   }
 
   createRenderRoot() {
@@ -208,8 +228,26 @@ class ElementView extends HTMLElement {
     }
     return this;
   }
-}
 
-Object.assign(ElementView.prototype, EventEmitter.prototype);
+  /**
+   * @param {any} obj
+   * @param {string} name
+   * @param {EventCallback} [callback]
+   * @return {EventEmitter}
+   */
+  listenTo(obj, name, callback) {
+    return this.emitter.listenTo.call(this, obj, name, callback);
+  }
+
+  /**
+   * @param {any} [obj]
+   * @param {string} [name]
+   * @param {EventCallback} [callback]
+   * @return {EventEmitter}
+   */
+  stopListening(obj, name, callback) {
+    return this.emitter.stopListening.call(this, obj, name, callback);
+  }
+}
 
 export default ElementView;
diff --git a/src/eventemitter.js b/src/eventemitter.js
index facb045..aff1fd6 100644
--- a/src/eventemitter.js
+++ b/src/eventemitter.js
@@ -78,7 +78,7 @@ class EventEmitter {
 
     if (error) throw error;
     // If the target obj is not Backbone.Events, track events manually.
-    if (listening.interop) listening.on(name, callback);
+    if (listening.interop) listening.start(name, callback, this);
 
     return this;
   }
@@ -124,7 +124,7 @@ class EventEmitter {
       if (!listening) break;
 
       listening.obj.off(name, callback, this);
-      if (listening.interop) listening.off(name, callback);
+      if (listening.interop) listening.stop(name, callback);
     }
     if (isEmpty(listeningTo)) this._listeningTo = undefined;
 
diff --git a/src/listening.js b/src/listening.js
index 2021a57..73e3088 100644
--- a/src/listening.js
+++ b/src/listening.js
@@ -1,4 +1,4 @@
-import { eventsApi,  offApi } from './utils/events.js';
+import { eventsApi, onApi, offApi } from './utils/events.js';
 
 /**
  * A listening class that tracks and cleans up memory bindings
@@ -21,6 +21,28 @@ class Listening {
     this._events = undefined;
   }
 
+  /**
+   * @param {string} name
+   * @param {Function} callback
+   * @param {any} context
+   */
+  start(name, callback, context) {
+    this._events = eventsApi(onApi, this._events || {}, name, callback, {
+      context: this.obj,
+      ctx: context,
+      listening: this,
+    });
+
+    const listeners = this.obj._listeners || (this.obj._listeners = {});
+    listeners[this.id] = this;
+
+    // Allow the listening to use a counter, instead of tracking
+    // callbacks for library interop
+    this.interop = false;
+
+    return this;
+  }
+
   /**
    * Stop's listening to a callback (or several).
    * Uses an optimized counter if the listenee uses Backbone.Events.
diff --git a/src/utils/events.js b/src/utils/events.js
index 9b67b84..35dcc6c 100644
--- a/src/utils/events.js
+++ b/src/utils/events.js
@@ -100,7 +100,7 @@ export function offApi(events, name, callback, options) {
         remaining.push(handler);
       } else {
         const listening = handler.listening;
-        if (listening) listening.off(name, callback);
+        if (listening) listening.stop(name, callback);
       }
     }