diff --git a/packages/core/__tests__/observable/observable-array.ts b/packages/core/__tests__/observable/observable-array.ts
index 8e2e5df06..a78ecd25f 100644
--- a/packages/core/__tests__/observable/observable-array.ts
+++ b/packages/core/__tests__/observable/observable-array.ts
@@ -44,4 +44,28 @@ describe('observable-array', () => {
 			assert.equal(0, _array.length);
 		});
 	});
+
+	describe('findIndex', () => {
+		it('finds an item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			const index = _array.findIndex((i) => i === 2);
+
+			assert.equal(1, index);
+		});
+
+		it('does not find item', () => {
+			const _array = new ObservableArray();
+
+			_array.push(1);
+			_array.push(2);
+
+			const index = _array.findIndex((i) => i === 3);
+
+			assert.equal(-1, index);
+		});
+	});
 });
diff --git a/packages/core/data/observable-array/index.ts b/packages/core/data/observable-array/index.ts
index 5dafad024..f927bacaa 100644
--- a/packages/core/data/observable-array/index.ts
+++ b/packages/core/data/observable-array/index.ts
@@ -288,6 +288,15 @@ export class ObservableArray<T> extends Observable {
 		return result;
 	}
 
+	/**
+	 * Returns the index of the first element in the array where predicate is true, and -1 otherwise.
+	 * @param predicate
+	 * @param thisArg If provided, it will be used as the this value for each invocation of predicate. If it is not provided, undefined is used instead.
+	 */
+	findIndex(predicate: (value: any, index: number, obj: any[]) => unknown, thisArg?: any): number {
+		return this._array.findIndex(predicate, thisArg);
+	}
+
 	/**
 	 * Returns the index of the first occurrence of a value in an array.
 	 * @param searchElement The value to locate in the array.