Add no-async-promise-executor lint rule (#4809)

.eslintrc.json

@@ -23,7 +23,8 @@
     "@typescript-eslint/ban-ts-ignore": ["off"],
     "@typescript-eslint/no-empty-function": ["off"],
     "no-return-await": "error",
-    "require-await": "error"
+    "require-await": "error",
+    "no-async-promise-executor": "error"
   },
   "overrides": [
     {

std/node/_fs/_fs_appendFile.ts

@@ -21,34 +21,31 @@ export function appendFile(
   }
 
   validateEncoding(options);
-
   let rid = -1;
-  new Promise(async (resolve, reject) => {
-    try {
-      if (typeof pathOrRid === "number") {
-        rid = pathOrRid;
-      } else {
-        const mode: number | undefined = isFileOptions(options)
-          ? options.mode
-          : undefined;
-        const flag: string | undefined = isFileOptions(options)
-          ? options.flag
-          : undefined;
+  const buffer: Uint8Array = new TextEncoder().encode(data);
+  new Promise((resolve, reject) => {
+    if (typeof pathOrRid === "number") {
+      rid = pathOrRid;
+      Deno.write(rid, buffer).then(resolve).catch(reject);
+    } else {
+      const mode: number | undefined = isFileOptions(options)
+        ? options.mode
+        : undefined;
+      const flag: string | undefined = isFileOptions(options)
+        ? options.flag
+        : undefined;
 
-        if (mode) {
-          //TODO rework once https://github.com/denoland/deno/issues/4017 completes
-          notImplemented("Deno does not yet support setting mode on create");
-        }
-        const file = await Deno.open(pathOrRid, getOpenOptions(flag));
-        rid = file.rid;
+      if (mode) {
+        //TODO rework once https://github.com/denoland/deno/issues/4017 completes
+        notImplemented("Deno does not yet support setting mode on create");
       }
-
-      const buffer: Uint8Array = new TextEncoder().encode(data);
-
-      await Deno.write(rid, buffer);
-      resolve();
-    } catch (err) {
-      reject(err);
+      Deno.open(pathOrRid, getOpenOptions(flag))
+        .then(({ rid: openedFileRid }) => {
+          rid = openedFileRid;
+          return Deno.write(openedFileRid, buffer);
+        })
+        .then(resolve)
+        .catch(reject);
     }
   })
     .then(() => {

std/node/_fs/_fs_chmod.ts

@@ -13,20 +13,9 @@ export function chmod(
   mode: string | number,
   callback: CallbackWithError
 ): void {
-  new Promise(async (resolve, reject) => {
-    try {
-      await Deno.chmod(path, getResolvedMode(mode));
-      resolve();
-    } catch (err) {
-      reject(err);
-    }
-  })
-    .then(() => {
-      callback();
-    })
-    .catch((err) => {
-      callback(err);
-    });
+  Deno.chmod(path, getResolvedMode(mode))
+    .then(() => callback())
+    .catch(callback);
 }
 
 /**

std/node/_fs/_fs_chown.ts

@@ -12,20 +12,9 @@ export function chown(
   gid: number,
   callback: CallbackWithError
 ): void {
-  new Promise(async (resolve, reject) => {
-    try {
-      await Deno.chown(path, uid, gid);
-      resolve();
-    } catch (err) {
-      reject(err);
-    }
-  })
-    .then(() => {
-      callback();
-    })
-    .catch((err) => {
-      callback(err);
-    });
+  Deno.chown(path, uid, gid)
+    .then(() => callback())
+    .catch(callback);
 }
 
 /**

std/node/_fs/_fs_copy.ts

@@ -7,20 +7,9 @@ export function copyFile(
   destination: string,
   callback: CallbackWithError
 ): void {
-  new Promise(async (resolve, reject) => {
-    try {
-      await Deno.copyFile(source, destination);
-      resolve();
-    } catch (err) {
-      reject(err);
-    }
-  })
-    .then(() => {
-      callback();
-    })
-    .catch((err) => {
-      callback(err);
-    });
+  Deno.copyFile(source, destination)
+    .then(() => callback())
+    .catch(callback);
 }
 
 export function copyFileSync(source: string, destination: string): void {

std/node/_fs/_fs_dir.ts

@@ -1,4 +1,5 @@
 import Dirent from "./_fs_dirent.ts";
+import { assert } from "../../testing/asserts.ts";
 
 export default class Dir {
   private dirPath: string | Uint8Array;
@@ -17,25 +18,25 @@ export default class Dir {
   }
 
   read(callback?: Function): Promise<Dirent | null> {
-    return new Promise(async (resolve, reject) => {
-      try {
-        if (!this.asyncIterator) {
-          this.asyncIterator = Deno.readdir(this.path)[Symbol.asyncIterator]();
-        }
-
-        const result: Dirent | null = await (await this.asyncIterator?.next())
-          .value;
-        resolve(result ? result : null);
-
-        if (callback) {
-          callback(null, result ? result : null);
-        }
-      } catch (err) {
-        if (callback) {
-          callback(err, null);
-        }
-        reject(err);
+    return new Promise((resolve, reject) => {
+      if (!this.asyncIterator) {
+        this.asyncIterator = Deno.readdir(this.path)[Symbol.asyncIterator]();
       }
+      assert(this.asyncIterator);
+      this.asyncIterator
+        .next()
+        .then(({ value }) => {
+          resolve(value ? value : null);
+          if (callback) {
+            callback(null, value ? value : null);
+          }
+        })
+        .catch((err) => {
+          if (callback) {
+            callback(err, null);
+          }
+          reject(err);
+        });
     });
   }
 

std/node/_fs/_fs_exists.ts

@@ -2,25 +2,23 @@
 
 type ExitsCallback = (exists: boolean) => void;
 
-/* Deprecated in node api */
-
+/**
+ * TODO: Also accept 'path' parameter as a Node polyfill Buffer or URL type once these
+ * are implemented. See https://github.com/denoland/deno/issues/3403
+ * Deprecated in node api
+ */
 export function exists(path: string, callback: ExitsCallback): void {
-  new Promise(async (resolve, reject) => {
-    try {
-      await Deno.lstat(path);
-      resolve();
-    } catch (err) {
-      reject(err);
-    }
-  })
+  Deno.lstat(path)
     .then(() => {
       callback(true);
     })
-    .catch(() => {
-      callback(false);
-    });
+    .catch(() => callback(false));
 }
 
+/**
+ * TODO: Also accept 'path' parameter as a Node polyfill Buffer or URL type once these
+ * are implemented. See https://github.com/denoland/deno/issues/3403
+ */
 export function existsSync(path: string): boolean {
   try {
     Deno.lstatSync(path);

std/node/_fs/_fs_mkdir.ts

@@ -1,7 +1,11 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { CallbackWithError } from "./_fs_common.ts";
 
-type Path = string; // TODO path can also be a Buffer or URL.
+/**
+ * TODO: Also accept 'path' parameter as a Node polyfill Buffer or URL type once these
+ * are implemented. See https://github.com/denoland/deno/issues/3403
+ */
+type Path = string;
 type MkdirOptions =
   | { recursive?: boolean; mode?: number | undefined }
   | number
@@ -29,14 +33,7 @@ export function mkdir(
     throw new Deno.errors.InvalidData(
       "invalid recursive option , must be a boolean"
     );
-  new Promise(async (resolve, reject) => {
-    try {
-      await Deno.mkdir(path, { recursive, mode });
-      resolve();
-    } catch (err) {
-      reject(err);
-    }
-  })
+  Deno.mkdir(path, { recursive, mode })
     .then(() => {
       if (callback && typeof callback == "function") {
         callback();