書式設定されていない JS コードを書式設定します。


1. イントロダクション

In today's digital era, JavaScript (JS) has become a fundamental language for web development. As JavaScript codebases grow in complexity, it's essential to maintain code readability and consistency. This is where a JS formatter comes into play. A JS formatter is a powerful tool that helps developers automatically format JavaScript code according to industry best practices. This post will explain the JS format's details and explore its numerous benefits.


A JS formatter is a software tool designed to analyze and reformat JavaScript code. It inputs unformatted or poorly formatted JavaScript code and changes it into a structured and standardized format. JS formatters enhance code readability, maintainability, and collaboration among developers working on the same codebase.

3. 特徴

3.1 機能1:コードのインデントとアライメント

One of the critical features of a JS formatter is its ability to handle code indentation and alignment automatically. It ensures consistent spacing and indentation throughout the codebase, making understanding its structure and hierarchy easier.

3.2 機能2:中括弧と括弧の配置

A JS formatter places braces and parentheses in JavaScript code. It eliminates inconsistencies in code style by enforcing a specific formatting standard. This feature improves code readability and prevents common syntax errors.

3.3 特徴3:行の折り返しと行の長さ

Long lines of code can be challenging to read and comprehend. A JS formatter breaks down long lines into multiple lines, adhering. Following a specified number of lines. This feature promotes better code understanding and avoids horizontal scrolling while reviewing or editing code.

3.4 機能4:インポートのソートとグループ化

When working with JavaScript modules and libraries, managing imports can become challenging. A JS formatter simplifies this task by automatically sorting and grouping import statements based on predefined rules. Grouping imports ensures a consistent and organized approach to importing dependencies into JavaScript projects.

3.5 機能5:末尾の空白と未使用のコードを削除する

To maintain a clean and efficient codebase, it's critical to eliminate unnecessary elements such as trailing whitespace and unused code. A JS formatter can automatically strip trailing whitespace and remove unused code snippets, improving code quality and reducing file size.

4. JSフォーマッタの使い方

Using a JS formatter is straightforward and typically involves a few simple steps:
1. Select a JS formatter that aligns with your coding preferences and project requirements.
2. You can install the formatter as a standalone tool, plugin, or extension for your preferred code editor. Once installed, you can configure the format's settings based on your desired code style.
3. You can manually run the formatter on your JavaScript files or enable automatic formatting on file save or during code commits.

5. JSフォーマッタの例

Several popular JS formatters are available on the market, each with features and configurations. One widely used formatter is Prettier, known for its simplicity and robust formatting capabilities. Another notable formatter is ESLint, a powerful linter providing code formatting rules. Prettier and ESLint offer integrations with popular code editors and build systems, making them accessible and convenient for developers.

6. 制限事項

While JS formatters offer numerous benefits, knowing their limitations is imperative. First, JS formatters rely on predefined rules and configurations, which may not align perfectly with every developer's coding style. It's crucial to balance code consistency and personal coding preferences. Additionally, JS formatters may struggle with complex or unconventional code patterns, requiring manual intervention in specific cases. It is worthwhile to review and test the formatted code to ensure it still functions as intended.


When using a JS formatter, it's critical to consider privacy and security. Most formatters operate locally on your machine and do not send code to external servers. However, it's advisable to review the privacy policy of the chosen formatter and ensure that it aligns with your data protection requirements. If you have concerns about sensitive code, you can opt for self-hosted formatters or offline solutions that do not rely on external services.


If you face any issues or have questions regarding a JS formatter, it's beneficial to have access to reliable customer support. Look for formatters that provide active community support through forums, documentation, and issue-tracking systems. Some formatters offer commercial support options for additional assistance and priority bug fixes.


Q1: JS フォーマッタの書式設定ルールをカスタマイズできますか?

Yes, many JS formatters allow you to customize their rules and configurations to match your preferred coding style. Rules customization enables you to tailor the formatted behavior according to your project's requirements.

Q2: JS フォーマッタはコードの機能を変更しますか?

No, a JS formatter focuses solely on code formatting and does not alter JavaScript code's functional logic. It ensures that your code follows consistent formatting standards without changing its behavior.

Q3: JS フォーマッタを既存のコード エディターと統合できますか。

Yes, most JS formatters offer integrations with popular code editors such as Visual Studio. 
Code, Sublime Text, and Atom. These integrations provide a seamless experience by enabling automatic code formatting within your preferred development environment.

Q4: JS フォーマッタをチーム設定で使用できますか?

Absolutely! JS formatters are highly beneficial in team settings as they promote code consistency and enhance collaboration. Using a formatter allows team members to follow a unified coding style, making code reviews and maintenance tasks much smoother.

Q5: JSフォーマッタを使用する場合のパフォーマンスに関する考慮事項はありますか?

While running a JS formatter on large codebases or complex files, there may be a slight delay in the formatting process. However, modern formatters are designed to be efficient and minimize the impact on the overall development workflow.

10. 関連ツール

Apart from JS formatters, other tools complement JavaScript development. Some notable ones include:

• リンター:

Tools like ESLint and JSHint help identify and enforce code quality standards, including formatting rules.

• バンドラー:

Tools like We pack and Parcel optimize JavaScript code for production deployments.

• テストフレームワーク:

Tools like Jest and Mocha provide a robust environment for testing JavaScript applications and libraries.


Tools like NPM and Yarn enable efficient management of JavaScript packages and dependencies.

• コードエディタ:

Popular code editors like Visual Studio Code, Sublime Text, and Atom offer extensive features and extensions that enhance JavaScript development.

11. まとめ

In conclusion, a JS formatter is valuable for developers looking to enhance JavaScript code readability and maintainability. By automating code formatting according to industry standards, a JS formatter improves collaboration, reduces manual effort, and ensures consistency across the codebase. With various features and customization options, developers can find a JS formatter that suits their needs. Embracing a JS formatter can significantly streamline the development process and contribute to JavaScript projects' quality.