Add require-await lint rule (#4401)

3 files changed, 12 insertions, 14 deletions

diff --git a/std/fs/copy_test.ts b/std/fs/copy_test.ts
index fb8827f0c..9ba5f2b21 100644
--- a/std/fs/copy_test.ts
+++ b/std/fs/copy_test.ts
@@ -17,10 +17,7 @@ const testdataDir = path.resolve("fs", "testdata");
 // TODO(axetroy): Add test for Windows once symlink is implemented for Windows.
 const isWindows = Deno.build.os === "win";
 
-async function testCopy(
-  name: string,
-  cb: (tempDir: string) => Promise<void>
-): Promise<void> {
+function testCopy(name: string, cb: (tempDir: string) => Promise<void>): void {
   Deno.test({
     name,
     async fn(): Promise<void> {
diff --git a/std/fs/exists.ts b/std/fs/exists.ts
index ae64cb1f3..f9e5a0925 100644
--- a/std/fs/exists.ts
+++ b/std/fs/exists.ts
@@ -4,15 +4,16 @@ const { lstat, lstatSync } = Deno;
  * Test whether or not the given path exists by checking with the file system
  */
 export async function exists(filePath: string): Promise<boolean> {
-  return lstat(filePath)
-    .then((): boolean => true)
-    .catch((err: Error): boolean => {
-      if (err instanceof Deno.errors.NotFound) {
-        return false;
-      }
+  try {
+    await lstat(filePath);
+    return true;
+  } catch (err) {
+    if (err instanceof Deno.errors.NotFound) {
+      return false;
+    }
 
-      throw err;
-    });
+    throw err;
+  }
 }
 
 /**
diff --git a/std/fs/walk_test.ts b/std/fs/walk_test.ts
index c2518cee3..96bfcae67 100644
--- a/std/fs/walk_test.ts
+++ b/std/fs/walk_test.ts
@@ -5,11 +5,11 @@ import { assert, assertEquals, assertThrowsAsync } from "../testing/asserts.ts";
 
 const isWindows = Deno.build.os == "win";
 
-export async function testWalk(
+export function testWalk(
   setup: (arg0: string) => void | Promise<void>,
   t: Deno.TestFunction,
   ignore = false
-): Promise<void> {
+): void {
   const name = t.name;
   async function fn(): Promise<void> {
     const origCwd = cwd();