diff --git a/src/util.ts b/src/util.ts
index a89c5351..6813322b 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -15,7 +15,7 @@ export async function ls(dir: string) {
   return Promise.all(paths.map(path => fs.stat(path).then(stat => ({path, stat}))))
 }
 
-export function wait(ms: number, unref: boolean = false): Promise<void> {
+export function wait(ms: number, unref = false): Promise<void> {
   return new Promise(resolve => {
     let t: any = setTimeout(() => resolve(), ms)
     if (unref) t.unref()