Merge from vscode 4d91d96e5e121b38d33508cdef17868bab255eae

extensions/github-browser/src/iterables.ts

@@ -0,0 +1,28 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+export namespace Iterables {
+	export function* filterMap<T, TMapped>(
+		source: Iterable<T> | IterableIterator<T>,
+		predicateMapper: (item: T) => TMapped | undefined | null,
+	): Iterable<TMapped> {
+		for (const item of source) {
+			const mapped = predicateMapper(item);
+			// eslint-disable-next-line eqeqeq
+			if (mapped != null) { yield mapped; }
+		}
+	}
+
+	export function* map<T, TMapped>(
+		source: Iterable<T> | IterableIterator<T>,
+		mapper: (item: T) => TMapped,
+	): Iterable<TMapped> {
+		for (const item of source) {
+			yield mapper(item);
+		}
+	}
+}