Skip reloadData in TimelineViewController when the articles array represents the same articles as the previous array. Just reload visible cells in that case.

NetNewsWire/MainWindow/Timeline/ArticleArray.swift

@@ -102,5 +102,20 @@ extension Array where Element == Article {
 		let articles = self.filter{ !$0.status.read }
 		return articles.isEmpty ? nil : articles
 	}
+
+	func representSameArticlesInSameOrder(as otherArticles: [Article]) -> Bool {
+		if self.count != otherArticles.count {
+			return false
+		}
+		var i = 0
+		for article in self {
+			let otherArticle = otherArticles[i]
+			if article.account != otherArticle.account || article.articleID != otherArticle.articleID {
+				return false
+			}
+			i += 1
+		}
+		return true
+	}
 }
 

NetNewsWire/MainWindow/Timeline/TimelineViewController.swift

@@ -28,11 +28,20 @@ class TimelineViewController: NSViewController, UndoableCommandRunner {
 
 	var articles = ArticleArray() {
 		didSet {
-			if articles != oldValue {
-				updateShowAvatars()
-				articleRowMap = [String: Int]()
-				tableView.reloadData()
+			if articles == oldValue {
+				return
 			}
+			if articles.representSameArticlesInSameOrder(as: oldValue) {
+				// When the array is the same — same articles, same order —
+				// but some data in some of the articles may have changed.
+				// Just reload visible cells in this case: don’t call reloadData.
+				articleRowMap = [String: Int]()
+				reloadVisibleCells()
+				return
+			}
+			updateShowAvatars()
+			articleRowMap = [String: Int]()
+			tableView.reloadData()
 		}
 	}
 
@@ -440,6 +449,13 @@ class TimelineViewController: NSViewController, UndoableCommandRunner {
 		}
 		return nil
 	}
+
+	private func reloadVisibleCells() {
+		guard let indexes = tableView.indexesOfAvailableRows() else {
+			return
+		}
+		reloadVisibleCells(for: indexes)
+	}
 	
 	private func reloadVisibleCells(for articles: [Article]) {
 		reloadVisibleCells(for: Set(articles.articleIDs()))