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How to change the indentation width in emacs javascript mode

Posted by: admin November 29, 2017 Leave a comment

Questions:

I’d like to use 2 spaces for my indents instead of 4. I can change the default behavior of C mode using:

(setq c-basic-offset 2)

How do I change this in javascript mode?

Answers:

js-indent-level can be used in the default javascript-mode, which is included by default starting in emacs 23.2.

(setq js-indent-level 2)

should do what you’re looking for. If you’re using an older version of emacs, you may be in java-mode. I think this mode responds to c-basic-offset, however I may be wrong.

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I wish someone had told me about Custom a lot sooner! Perhaps this will help another mere mortal like me 😉

Invoke Custom:

M-x customize

Then, choose “Programming,” and then “Languages,” and then select a language/mode to customize. Edit the options as you see fit. When done, choose either “Save for current session” or “Save for future sessions.”

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If you’re using js2-mode (which is more powerful IMHO), then the command is:

(setq-default js2-basic-offset 2)

Source.

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You might also want to set emacs to use spaces instead of tabs

(setq-default indent-tabs-mode nil)

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In my javascript.el file (/usr/share/emacs/site-lisp) I found

javascript-indent-level 4

So if you are using the same lisp-mode you can change it by running

(setq javascript-indent-level 2)

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You can also use

M-x customize-variable

and type

js-indent-level

(js- [TAB] shows a list of options). Then change the Js Indent Level as wanted and click [State:] and save.

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Using EditorConfig could be a good idea too. And of course, Emacs had a mode for it editorconfig-emacs.

It’s also available in the package manager (M-x package-list-packages) through Melpa or Marmalade.

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If you want to change it on a per-file basis, put this at the top of your file:

// -*- mode: js; js-indent-level: 2; -*-