LearnSass Tip: The Double Ampersand Selector

In Sass, the ampersand (&) symbol is used to reference the parent selector in a nested rule. For example, the following targets .btn on :hover:

.btn {
  ...
  &:hover {
    background: dodgerblue;
  }
}

We can also place the & after a selector to reverse the nesting order:

.btn {
  ...
  .navbar & {
    background: lightsteelblue;
  }
}

This outputs a descendant selector that targets a .btn element inside .navbar:

.btn {
  ...
}
.navbar .btn {
  background: lightsteelblue;
}

We can take this concept a step further with an adjacent sibling combinator.

Adjacent Sibling Selector

The adjacent sibling combinator (+) is used to target an element’s immediate sibling. For instance:

.heading + .intro {
  ...
}

This targets any intro class immediately following an element with the class heading. Let’s take a look at two useful ways we can use this combinator with the & selector.

Adjacent Buttons

Let’s say we have a button group consisting of a primary and a secondary action button, both have the class btn.

<div class="btn-group">
  <a class="btn" href="#">Primary Action</a>
  <a class="btn" href="#">Secondary Action</a>
</div>

The secondary action button needs to be a different color and have a left margin to separate it from its sibling. We can use the following rule to reference btn, then target its immediate sibling with the same class:

.btn {
  ...
  & + & {
    margin-left: 15px;
    background: firebrick;
  }
}

If two btn classes are adjacent siblings, the second one will get the firebrick background and left margin. Here’s the CSS output:

.btn {
  ...
}
.btn + .btn {
  margin-left: 15px;
  background: firebrick;
}

See CodePen Demo

Columns

The adjacent & selector also helps with column layout. To create a row where all but the first column have a left margin (or gutter), we can write the following:

.col {
  ...
  & + & {
    margin-left: 30px;
  }
}

The first column will remain flush with the left side of the page, while the others get a roomy left margin.

See CodePen Demo

As we just learned, the “double ampersand” sibling selector is a handy solution that keeps us from writing extra CSS and classes in our markup. Methods like these are some of the many ways Sass helps us write cleaner, more efficient front-end code.

To learn more about Sass, check out our new Treehouse course on Sass basics.

9 Responses to “Sass Tip: The Double Ampersand Selector”

  1. Mário Silva on March 28, 2017 at 9:44 am said:

    Hello,
    Did any of you guys ever tried to use the following code:

    SOURCE
    ´´´
    .bananas,
    .kiwis {
    prop: props;
    @at-root .strawberry#{&} {
    prop: strawberry;
    }
    }
    ´´´

    OUTPUT
    ´´´
    .bananas,
    .kiwis {
    prop: props;
    }
    .strawberry.bananas,
    .kiwis {
    prop: strawberry;
    }
    ´´´

    I cant manage to join strawberry to kiwis.

  2. This is awesome, I just found it and you have saved me some extra work already! love it!

  3. 銆愰€佹枡鐒℃枡銆慡alvatore Ferragamo(銈点儷銉淬偂銉堛兗銉兓銉曘偋銉┿偓銉?鈼嗐兇銈°儵銉儨銉?way銉忋兂銉?銈淬兗銉儔*銉偠銉?銉淬偅銉炽儐銉笺偢 /K05208/銆愪唬寮曘亶鎵嬫暟鏂欑 on January 22, 2016 at 11:57 pm said:

    Wow, wonderful blog layout! How long have you been blogging for? you made blogging look easy. The overall look of your site is excellent, as well as the content!

  4. Dallas Designs on January 2, 2014 at 5:18 am said:

    Awesome articles you posted here i am so inspired here keep it continue.
    Thanks

  5. Christopher Dell'Olio on December 30, 2013 at 9:45 am said:

    I am becoming very fond of Treehouse articles. Love staying up to date on the modern web technology! 🙂

  6. Sass 3.3 is coming, all this stuff will be even more awesome! 😀

    https://gist.github.com/luzlol/7940531

    • matthew carleton on December 29, 2013 at 7:56 pm said:

      Hey this is fantastic. Ordinarily I would apply the margin to all and then remove with first-child, this is better with less code! Thanks.

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