From 85bca2e7785dcb9bd5aab6325a73b198cec89973 Mon Sep 17 00:00:00 2001
From: Yagiz Nizipli <yagiz@nizipli.com>
Date: Mon, 10 Jul 2023 06:52:20 -0400
Subject: [PATCH] refactor: avoid unnecessary async scopes in eslint (#52418)

This pull request:
- removes unnecessary object copying in `hasEslintConfiguration`
- returns always `null` on `runLintCheck`, and make sure it does not return undefined.
- removes unnecessary async scope creation on `isDirectory`
---
 .../src/lib/eslint/hasEslintConfiguration.ts  | 12 +++++----
 packages/next/src/lib/eslint/runLintCheck.ts  |  6 ++---
 .../next/src/lib/eslint/writeOutputFile.ts    | 25 ++++++++++---------
 3 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/packages/next/src/lib/eslint/hasEslintConfiguration.ts b/packages/next/src/lib/eslint/hasEslintConfiguration.ts
index 6c600f545478c..4d77920813e80 100644
--- a/packages/next/src/lib/eslint/hasEslintConfiguration.ts
+++ b/packages/next/src/lib/eslint/hasEslintConfiguration.ts
@@ -29,14 +29,16 @@ export async function hasEslintConfiguration(
       content === '---' ||
       content === 'module.exports = {}'
     ) {
-      return { ...configObject, emptyEslintrc: true }
+      configObject.emptyEslintrc = true
+    } else {
+      configObject.exists = true
     }
-    return { ...configObject, exists: true }
   } else if (packageJsonConfig?.eslintConfig) {
-    if (Object.keys(packageJsonConfig?.eslintConfig).length) {
-      return { ...configObject, exists: true }
+    if (Object.keys(packageJsonConfig.eslintConfig).length) {
+      configObject.exists = true
+    } else {
+      configObject.emptyPkgJsonConfig = true
     }
-    return { ...configObject, emptyPkgJsonConfig: true }
   }
   return configObject
 }
diff --git a/packages/next/src/lib/eslint/runLintCheck.ts b/packages/next/src/lib/eslint/runLintCheck.ts
index 528aecd570f4d..077a26cd0f1c6 100644
--- a/packages/next/src/lib/eslint/runLintCheck.ts
+++ b/packages/next/src/lib/eslint/runLintCheck.ts
@@ -43,7 +43,7 @@ const requiredPackages = [
   },
 ]
 
-async function cliPrompt() {
+async function cliPrompt(): Promise<{ config?: any }> {
   console.log(
     chalk.bold(
       `${chalk.cyan(
@@ -72,7 +72,7 @@ async function cliPrompt() {
       unselected: '  ',
     })
 
-    return { config: value?.config }
+    return { config: value?.config ?? null }
   } catch {
     return { config: null }
   }
@@ -131,7 +131,7 @@ async function lint(
     const mod = await Promise.resolve(require(deps.resolved.get('eslint')!))
 
     const { ESLint } = mod
-    let eslintVersion = ESLint?.version ?? mod?.CLIEngine?.version
+    let eslintVersion = ESLint?.version ?? mod.CLIEngine?.version
 
     if (!eslintVersion || semver.lt(eslintVersion, '7.0.0')) {
       return `${chalk.red(
diff --git a/packages/next/src/lib/eslint/writeOutputFile.ts b/packages/next/src/lib/eslint/writeOutputFile.ts
index cef79393b0378..2666b8d1b9442 100644
--- a/packages/next/src/lib/eslint/writeOutputFile.ts
+++ b/packages/next/src/lib/eslint/writeOutputFile.ts
@@ -7,21 +7,22 @@ import isError from '../../lib/is-error'
  * Check if a given file path is a directory or not.
  * Returns `true` if the path is a directory.
  */
-async function isDirectory(
+function isDirectory(
   /**  The path to a file to check. */
   filePath: string
 ): Promise<boolean> {
-  try {
-    return (await fs.stat(filePath)).isDirectory()
-  } catch (error) {
-    if (
-      isError(error) &&
-      (error.code === 'ENOENT' || error.code === 'ENOTDIR')
-    ) {
-      return false
-    }
-    throw error
-  }
+  return fs
+    .stat(filePath)
+    .then((stat) => stat.isDirectory())
+    .catch((error) => {
+      if (
+        isError(error) &&
+        (error.code === 'ENOENT' || error.code === 'ENOTDIR')
+      ) {
+        return false
+      }
+      throw error
+    })
 }
 /**
  * Create a file with eslint output data