arrays.insert

src/vs/base/common/arrays.ts

@@ -265,4 +265,19 @@ export function index<T,R>(array: T[], indexer: (t: T) => string, merger: (t: T,
 		r[key] = merger(t, r[key]);
 		return r;
 	}, Object.create(null));
+}
+
+/**
+ * Inserts an element into an array. Returns a function which, when
+ * called, will remove that element from the array.
+ */
+export function insert<T>(array: T[], element: T): () => void {
+	array.push(element);
+
+	return () => {
+		const index = array.indexOf(element);
+		if (index > -1) {
+			array.splice(index, 1);
+		}
+	};
 }
\ No newline at end of file