Prettier + ESLint の開発環境でeslint.config.jsに「parsing error the keyword 'import' is reserved」が表示される場合の解消法

## エラー現象
開発環境にPrettierとESLintを導入すると、以下のようなESLintエラーが表示される。
`parsing error the keyword 'import' is reserved`

![ESLintエラー1.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/2292896/2270ce93-be55-8a8a-6840-05d94b36bfcd.jpeg)

## 開発環境
### package.json
```json:package.json
{
    "name": "hair-salon-site",
    "private": true,
    "version": "0.0.0",
    "type": "module",
    "scripts": {
        "dev": "vite",
        "build": "tsc && vite build",
        "lint": "eslint src",
        "lint:fix": "eslint src --fix",
        "preview": "vite preview",
        "test": "vitest",
        "test:watch": "vitest watch",
        "coverage": "vitest run --coverage",
        "prepare": "husky",
        "storybook": "storybook dev -p 6006",
        "build-storybook": "storybook build"
    },
    "dependencies": {
        "@emotion/react": "^11.11.4",
        "@emotion/styled": "^11.11.5",
        "@mui/material": "^5.15.18",
        "react": "^18.2.0",
        "react-dom": "^18.2.0"
    },
    "devDependencies": {
        "@chromatic-com/storybook": "^1.4.0",
        "@eslint/js": "^9.2.0",
        "@storybook/addon-essentials": "^8.1.1",
        "@storybook/addon-interactions": "^8.1.1",
        "@storybook/addon-links": "^8.1.1",
        "@storybook/addon-onboarding": "^8.1.1",
        "@storybook/blocks": "^8.1.1",
        "@storybook/react": "^8.1.1",
        "@storybook/react-vite": "^8.1.1",
        "@storybook/test": "^8.1.1",
        "@testing-library/jest-dom": "^6.4.5",
        "@testing-library/react": "^15.0.7",
        "@testing-library/user-event": "^14.5.2",
        "@types/react": "^18.2.66",
        "@types/react-dom": "^18.2.22",
        "@typescript-eslint/eslint-plugin": "^7.2.0",
        "@typescript-eslint/parser": "^7.2.0",
        "@vitejs/plugin-react-swc": "^3.5.0",
        "@vitest/coverage-v8": "^1.6.0",
        "eslint": "^8.57.0",
        "eslint-config-prettier": "^9.1.0",
        "eslint-plugin-perfectionist": "^2.10.0",
        "eslint-plugin-react": "^7.34.1",
        "eslint-plugin-react-hooks": "^4.6.0",
        "eslint-plugin-react-refresh": "^0.4.6",
        "eslint-plugin-storybook": "^0.8.0",
        "globals": "^15.2.0",
        "happy-dom": "^14.10.1",
        "husky": "^9.0.11",
        "lint-staged": "^15.2.2",
        "prettier": "3.2.5",
        "sass": "^1.77.1",
        "storybook": "^8.1.1",
        "typescript": "^5.2.2",
        "typescript-eslint": "^7.8.0",
        "vite": "^5.2.0",
        "vite-tsconfig-paths": "^4.3.2",
        "vitest": "^1.6.0"
    },
    "lint-staged": {
        "*.{js,jsx,ts,tsx}": [
            "prettier --write",
            "eslint --fix"
        ]
    },
    "eslintConfig": {
        "extends": [
            "plugin:storybook/recommended"
        ]
    }
}
```
### eslint.config.js
```javascript:eslint.config.js
import pluginJs from "@eslint/js";
import eslintConfigPrettier from "eslint-config-prettier";
import perfectionistNatural from "eslint-plugin-perfectionist/configs/recommended-natural";
import react from "eslint-plugin-react";
import globals from "globals";
import tseslint from "typescript-eslint";

export default [
  {
    files: ["**/*.{js,ts,jsx,tsx}"],
    languageOptions: { globals: globals.browser },
    plugins: { react },
    rules: {
      /** target-blank(セキュリティ対策)の検知活性 */
      "react/jsx-no-target-blank": "error",
      /** react指定の除外 */
      "react/react-in-jsx-scope": "off",
    },
  },
  pluginJs.configs.recommended,
  ...tseslint.configs.recommended,
  /** props、importなどをソート管理するもの */
  perfectionistNatural,
  eslintConfigPrettier,
];
```
### .prettierrc
導入直後のため記載なし

## 試したこと
以下の記事内容を参考し、`parserOptions`関連を設定をしたが改善されなかった。

https://qiita.com/kozzzz/items/be3a5f326311b6784860

## 解決方法
以下のページの一番最後のコメントにて

*VSCode and open the settings and just search for "useFlatConfig", turned it on and the error went aways.*
(VSCodeで設定を開き、「useFlatConfig 」を検索して、それをオンにしたら、エラーはなくなった。)

と書かれていたため、試してみると該当エラーが出なくなった。

https://stackoverflow.com/questions/75524079/eslint-flat-config-eslint-config-js-throwing-parsing-error-the-keyword-imp

![ESLintエラー2.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/2292896/887a826b-a825-88b8-70cc-24ec95d533a0.jpeg)

![ESLintエラー3.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/2292896/95227c13-c584-13c8-d450-0d5a1f69b236.jpeg)

## おわりに
ESLintのflat config（フラット構成）に関連する記事や情報サイトがほとんどないため、問題解決に難儀した。
これから関連記事が増えていくことを願うばかり・・・:thinking: