DEV: Convert eyeline & posts-with-placeholders to native class syntax (#28609)

app/assets/javascripts/discourse/app/lib/eyeline.js

@@ -19,7 +19,7 @@ export function configureEyeline(opts) {
 configureEyeline();
 
 // Track visible elements on the screen.
-export default EmberObject.extend(Evented, {
+export default class Eyeline extends EmberObject.extend(Evented) {
   update() {
     if (_skipUpdate) {
       return;
@@ -81,5 +81,5 @@ export default EmberObject.extend(Evented, {
         return this.trigger("sawBottom", { detail: $elem });
       }
     });
-  },
-});
+  }
+}

app/assets/javascripts/discourse/app/lib/posts-with-placeholders.js

@@ -10,52 +10,50 @@ export function Placeholder(viewName) {
   this.viewName = viewName;
 }
 
-export default EmberObject.extend(EmberArray, {
-  posts: null,
-  _appendingIds: null,
-
-  init() {
-    this._appendingIds = {};
-  },
+export default class PostsWithPlaceholders extends EmberObject.extend(
+  EmberArray
+) {
+  posts = null;
+  _appendingIds = {};
 
   @discourseComputed
   length() {
     return (
       this.get("posts.length") + Object.keys(this._appendingIds || {}).length
     );
-  },
+  }
 
   nextObject(index) {
     return this.objectAt(index);
-  },
+  }
 
   _changeArray(cb, offset, removed, inserted) {
     arrayContentWillChange(this, offset, removed, inserted);
     cb();
     arrayContentDidChange(this, offset, removed, inserted);
     this.notifyPropertyChange("length");
-  },
+  }
 
   clear(cb) {
     this._changeArray(cb, 0, this.get("posts.length"), 0);
-  },
+  }
 
   appendPost(cb) {
     this._changeArray(cb, this.get("posts.length"), 0, 1);
-  },
+  }
 
   removePost(cb) {
     this._changeArray(cb, this.get("posts.length") - 1, 1, 0);
-  },
+  }
 
   insertPost(insertAtIndex, cb) {
     this._changeArray(cb, insertAtIndex, 0, 1);
-  },
+  }
 
   refreshAll(cb) {
     const length = this.get("posts.length");
     this._changeArray(cb, 0, length, length);
-  },
+  }
 
   appending(postIds) {
     this._changeArray(
@@ -67,7 +65,7 @@ export default EmberObject.extend(EmberArray, {
       0,
       postIds.length
     );
-  },
+  }
 
   finishedAppending(postIds) {
     this._changeArray(
@@ -79,16 +77,16 @@ export default EmberObject.extend(EmberArray, {
       postIds.length,
       postIds.length
     );
-  },
+  }
 
   finishedPrepending(postIds) {
     this._changeArray(function () {}, 0, 0, postIds.length);
-  },
+  }
 
   objectAt(index) {
     const posts = this.posts;
     return index < posts.length
       ? posts[index]
       : new Placeholder("post-placeholder");
-  },
-});
+  }
+}