From 3ddfb5c34a3f7d7ad9d092a87b1cfebbc2ab5b07 Mon Sep 17 00:00:00 2001
From: matthewianmorgan <matthewianmorgan@gmail.com>
Date: Mon, 1 Feb 2021 04:05:37 +1000
Subject: [PATCH] fix(core): ObservableArray splice with start only (#9159)

---
 .../__tests__/observable/observable-array.ts  | 47 +++++++++++++++++++
 packages/core/data/observable-array/index.ts  |  2 +-
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 packages/core/__tests__/observable/observable-array.ts

diff --git a/packages/core/__tests__/observable/observable-array.ts b/packages/core/__tests__/observable/observable-array.ts
new file mode 100644
index 000000000..8e2e5df06
--- /dev/null
+++ b/packages/core/__tests__/observable/observable-array.ts
@@ -0,0 +1,47 @@
+import { ObservableArray } from '@nativescript/core/data/observable-array';
+import { assert } from 'chai';
+
+describe('observable-array', () => {
+	describe('splice', () => {
+		it('removes an item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			_array.splice(0, 1);
+
+			assert.equal(2, _array.getItem(0));
+		});
+
+		it('replaces an item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			_array.splice(0, 1, 3);
+
+			assert.equal(3, _array.getItem(0));
+		});
+
+		it('empties on start zero and no delete count', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+
+			_array.splice(0);
+			assert.equal(0, _array.length);
+		});
+
+		it('empties on length set to zero', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			_array.length = 0;
+			assert.equal(0, _array.length);
+		});
+	});
+});
diff --git a/packages/core/data/observable-array/index.ts b/packages/core/data/observable-array/index.ts
index 12f7351d9..5dafad024 100644
--- a/packages/core/data/observable-array/index.ts
+++ b/packages/core/data/observable-array/index.ts
@@ -246,7 +246,7 @@ export class ObservableArray<T> extends Observable {
 	 */
 	splice(start: number, deleteCount?: number, ...items: any): T[] {
 		const length = this._array.length;
-		const result = this._array.splice(start, deleteCount, ...items);
+		const result = arguments.length === 1 ? this._array.splice(start) : this._array.splice(start, deleteCount, ...items);
 
 		this.notify(<ChangedData<T>>{
 			eventName: CHANGE,