diff --git a/src/lib/times.ts b/src/lib/times.ts
deleted file mode 100644
index 3c1f10f..0000000
--- a/src/lib/times.ts
+++ /dev/null
@@ -1,4 +0,0 @@
-export const times = <T>(n: number, fn: (num: number) => T): T[] =>
-  Array(n)
-    .fill(undefined)
-    .map((_, i) => fn(i));
diff --git a/src/lib/util.ts b/src/lib/util.ts
index a9e4cb9..7b42147 100644
--- a/src/lib/util.ts
+++ b/src/lib/util.ts
@@ -1,3 +1,11 @@
 export function isDefined<T>(value: T | undefined | null): value is T {
   return <T>value !== undefined && <T>value !== null;
 }
+
+export const isPromise = (val: void | Promise<any>): val is Promise<any> =>
+  val && (<Promise<any>>val).then !== undefined;
+
+export const times = <T>(n: number, fn: (num: number) => T): T[] =>
+  Array(n)
+    .fill(undefined)
+    .map((_, i) => fn(i));