I haven't been able to figure this out yet. Atom seems to use spaces as the default indentation mode. I prefer to have tabs instead though. Sublime Text has built in functionality for switching and converting indentation.
Anyone found out how to change the indentation mode of Atom?
Some screenshots from Sublime Text:
Go to File -> Settings
There are 3 different options here.
I did some testing and have come to these conclusions about what each one does.
Soft Tabs - Enabling this means it will use spaces by default (i.e. for new files).
Tab Length - How wide the tab character displays, or how many spaces are inserted for a tab if soft tabs is enabled.
Tab Type - This determines the indentation mode to use for existing files. If you set it to auto it will use the existing indentation (tabs or spaces). If you set it to soft or hard, it will force spaces or tabs regardless of the existing indentation. Best to leave this on auto.
Note: Soft = spaces, hard = tab
Late to the party, but a clean way to do this on a per-project basis, is to add a .editorconfig file to the root of the project. Saves you from having to change Atom's settings when you're working on several projects simultaneously.
This is a sample of a very basic setup I'm currently using. Works for Atom, ST, etc...
# Automatically add new line to end of all files on save.
[*]
insert_final_newline = true
# 2 space indentation for SASS/CSS
[*.{scss,sass,css}]
indent_style = space
indent_size = 2
# Set all JS to tab => space*2
[js/**.js]
indent_style = space
indent_size = 2
This is built into core: See Settings ⇒ Tab Type and choose auto:
When set to "auto", the editor auto-detects the tab type based on the contents of the buffer (it uses the first leading whitespace on a non-comment line), or uses the value of the Soft Tabs config setting if auto-detection fails.
You may also want to take a look at the Auto Detect Indentation package. From the docs:
Automatically detect indentation of opened files. It looks at each opened file and sets file specific tab settings (hard/soft tabs, tab length) based on the content of the file instead of always using the editor defaults.
You might have atom configured to use 4 spaces for tabs but open a rails project which defaults to 2 spaces. Without this package, you would have to change your tabstop settings globally or risk having inconsistent lead spacing in your files.
Tab Control gives nice control in a similar manner to that described in your question.
Also nice, for JavaScript developers, is ESLint Tab Length for using ESLint config.
Or if you're using an .editorconfig for defining project-specific indentation rules, there is EditorConfig
If you're using Babel you may also want to make sure to update your "Language Babel" package. For me, even though I had the Tab Length set to 2 in my core editor settings, the Same setting in the Language Babel config was overriding it with 4.
Atom -> Preferences -> Packages -> (Search for Babel) -> Grammar -> Tab Length
Make sure the appropriate Grammar, There's "Babel ES6 Javascript Grammar", "language-babel-extension Grammar" as well as "Regular Expression". You probably want to update all of them to be consistent.
If global tab/spaces indentation settings no longer fit your needs (I.E. you find yourself working with legacy codebases with varied indentation formats, and you need to quickly switch between them, and the auto-detect isn't working) you might try the tab-control plugin, which sort of duplicates the functionality of the menu in your screenshot.
When Atom auto-indent-detection got it hopelessly wrong and refused to let me type a literal Tab character, I eventually found the 'Force-Tab' extension - which gave me back control. I wanted to keep shift-tab for outdenting, so set ctrl-tab to insert a hard tab. In my keymap I added:
'atom-text-editor':
'ctrl-tab': 'force-tab:insert-actual-tab'
Changing language-specific configuration
I changed the default tab settings, and it still did not impact when I was editing my files, which were Python files. It also did not change when I modified the "*" setting in ~/.atom/config.cson . I don't have a good explanation for either of those.
However, when I added the following to my config.cson, I was able to change the tab in my Python files to 2 spaces:
'.source.python':
editor:
tabLength: 2
Thanks to this resource for the solution: Tab key not respecting tab length
All of the most popular answers on here are all great answers and will turn on spaces for tabs, but they are all missing one thing. How to apply the spaces instead of tabs to existing code.
To do this simply select all the code you want to format, then go to Edit->Lines->Auto Indent and it will fix everything selected.
Alternatively, you can just select all the code you want to format, then use Ctrl Shift P and search for Auto Indent. Just click it in the search results and it will fix everything selected.
