Solving Indentation Issues in js2-mode for Emacs

If you’re a JavaScript developer using Emacs with js2-mode, you may have encountered an irritating problem: the editor uses tabs instead of spaces for indentation. This can disrupt your coding workflow and lead to formatting inconsistencies in your JavaScript files. Luckily, fixing this issue is straightforward!

In this post, we’ll walk you through the simple steps required to ensure js2-mode uses spaces for indentation.

The Problem: Default Tab Indentation

When using js2-mode, you may notice that indentation behaves differently compared to other modes in Emacs. The main issue arises when insert-mode uses tabs instead of spaces, which is essential for many JavaScript style guides. Understanding why this happens can help us address the problem effectively.

The Solution: Configuring Emacs

To configure js2-mode to use spaces rather than tabs, you need to adjust the settings in your Emacs configuration file, typically named .emacs or init.el. Here’s how to do it:

Step 1: Open Your Configuration File

You need to locate and open your .emacs or init.el file:

• Open Emacs.
• Use the command C-x C-f (Control + x followed by Control + f) to open a file.
• Type ~/.emacs or ~/.emacs.d/init.el and hit Enter.

Step 2: Add the Indentation Setting

Now, you will want to insert a specific line of code that dictates how Emacs handles indentation:

(setq-default indent-tabs-mode nil)

Explanation of the Code

• setq-default: This function sets the default value of a variable. In our case, we are setting indent-tabs-mode.
• indent-tabs-mode: This variable controls whether Emacs uses tabs or spaces for indentation. Setting it to nil tells Emacs to use spaces for all modes where this setting is applicable.

Step 3: Save and Restart Emacs

After you’ve added the line of code:

• Save the file using C-x C-s (Control + x followed by Control + s).
• Restart Emacs to apply the changes.

Verify Your Changes

To ensure that your configuration works:

1. Open a JavaScript file in js2-mode.
2. Try indenting a line of code. You should see spaces being used for indentation instead of tabs.

Conclusion

By following these simple steps, you can easily configure js2-mode in Emacs to use spaces instead of tabs for indentation. This adjustment not only helps in maintaining consistency in your coding styles but also aligns with widely accepted JavaScript coding conventions.

Now you can code without worrying about formatting issues. Happy coding!