Why put in front of the file name “_” or “_” in sc

Question

Why put _ in front of the filename in scss?

_filename.scss - Why does it need _ ?

Answer 1

A sass file starting with an underscore is a partial. It is a good way to keep your styles separated into logical sections. These files all get merged on compilation when you use @import.

From the Sass language guide:

You can create partial Sass files that contain little snippets of CSS that you can include in other Sass files. This is a great way to modularize your CSS and help keep things easier to maintain. A partial is simply a Sass file named with a leading underscore. You might name it something like _partial.scss. The underscore lets Sass know that the file is only a partial file and that it should not be generated into a CSS file. Sass partials are used with the @import directive.

http://sass-lang.com/guide

Answer 2

When you include "_" in front of the file name, it won't be generated into CSS unless you import it into another sass files which is not partial.

suppose your folder structure is like this

/scss
 style.scss
 _list.scss
/css

if you run the command

sass --watch scss:css

only style.css and style.css.map files will be created, sass compiler will omit _list.scss without converting its content into a CSS file.

/scss
 style.scss
 _list.scss
/css
 style.css
 style.css.map

the only way that you can use partials is to import them into another .scss file with

@import 'list.scss';

if you remove the '_' in front of _test.scss the outcome of the command will be

/scss
 style.scss
 _list.scss
/css
 style.css
 style.css.map
 test.css
 test.css.map

The main purpose of using partials is to break down our CSS code into several pieces which are easier to maintain. Hope this helps. Thanks.

Answer 3

Files with _ (underscore) are ignored by compiler. However, all those files are imported into single, main SCSS file (i.e. styles.scss) which is actually the file that is compiled (it doesn't have _ (underscore) in it's name)

The final goal is to compile only one SCSS file, and to have only one CSS file as a result of that, which has various advantages.

Answer 4

The _ (underscore) is a partial for scss. That means the stylesheet its going to be imported (@import) to a main stylesheet i.e. styles.scss. The advantage on using partials is that you can use many files to organize your code and everything will be compiled on a single file.