Combining & with BEM naming in SASS

Introduction

Using & with BEM helps write cleaner CSS by nesting styles for blocks, elements, and modifiers together.

When you want to style a block and its elements in one place.

When you need to add a modifier style to a block or element.

When you want to keep your CSS organized and easy to read.

When you want to avoid repeating the full class names.

When you want to write less code but keep clear naming.

Syntax

SASS

.block {
  &__element {
    // styles for element
  }
  &--modifier {
    // styles for modifier
  }
}

The & symbol means "use the parent selector here".

BEM uses __ for elements and -- for modifiers.

Examples

This styles the button__icon element inside the button block.

SASS

.button {
  &__icon {
    color: blue;
  }
}

This styles the button--large modifier of the button block.

SASS

.button {
  &--large {
    font-size: 2rem;
  }
}

This styles both an element card__title and a modifier card--highlighted inside the card block.

SASS

.card {
  &__title {
    font-weight: bold;
  }
  &--highlighted {
    background: yellow;
  }
}

Sample Program

This example shows a menu block with items as elements and an active item as a modifier. The CSS uses BEM naming combined with & in Sass (shown here as compiled CSS) to style them clearly.

SASS

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>BEM with & in Sass</title>
  <style>
    .menu {
      background: #eee;
      padding: 1rem;
    }
    .menu__item {
      color: #333;
      padding: 0.5rem;
    }
    .menu__item--active {
      color: white;
      background: #007acc;
      font-weight: bold;
    }
  </style>
</head>
<body>
  <nav class="menu">
    <div class="menu__item">Home</div>
    <div class="menu__item menu__item--active">About</div>
    <div class="menu__item">Contact</div>
  </nav>
</body>
</html>

Important Notes

Remember to compile Sass to CSS before using it in the browser.

Using & keeps your styles connected to the parent block, making your CSS easier to maintain.

Summary

Combining & with BEM helps write neat, organized CSS.

Use &__element for elements and &--modifier for modifiers inside a block.

This method reduces repetition and keeps styles easy to find and update.

Practice

1. What does the & symbol represent when used in Sass with BEM naming?

easy

A. It resets all styles inside the block.

B. It creates a new CSS class unrelated to the parent.

C. It imports external CSS files.

D. It refers to the current parent selector in the nested block.

Solution

1. Step 1: Understand the role of & in Sass

   The & symbol in Sass means "use the current parent selector" inside nested rules.

2. Step 2: Connect with BEM naming

   When combined with BEM, &__element or &--modifier appends to the parent block's class name.

3. Final Answer:

   It refers to the current parent selector in the nested block. -> Option D

4. Quick Check:

   & = current parent selector [OK]

Hint: Remember & means "this block" in nested Sass [OK]

Common Mistakes:

• Thinking & creates a new unrelated class
• Confusing & with a CSS variable
• Using & to import files

2. Which of the following Sass snippets correctly uses & to create a BEM modifier for a block named .card?

easy

A. &__active { background: green; }

B. .card--active { background: green; }

C. &--active { background: green; }

D. &-active { background: green; }

Solution

1. Step 1: Identify BEM modifier syntax

   Modifiers use double dashes: --modifier, so &--active appends --active to the parent block.

2. Step 2: Check other options

   .card--active { background: green; } repeats the full class, not using &. &__active { background: green; } uses __ which is for elements, not modifiers. &-active { background: green; } uses a single dash, which is incorrect for BEM modifiers.

3. Final Answer:

   &--active { background: green; } -> Option C

4. Quick Check:

   Modifier = &--modifier [OK]

Hint: Use &--modifier for modifiers inside blocks [OK]

Common Mistakes:

• Using single dash instead of double dash for modifiers
• Confusing elements (__element) with modifiers (--modifier)
• Writing full class name instead of using &

3. Given the Sass code below, what CSS will it generate?

.button {
  color: blue;
  &__icon {
    margin-right: 0.5rem;
  }
  &--large {
    font-size: 2rem;
  }
}

medium

A. .button { color: blue; } &__icon { margin-right: 0.5rem; } &--large { font-size: 2rem; }

B. .button { color: blue; } .button__icon { margin-right: 0.5rem; } .button--large { font-size: 2rem; }

C. .button { color: blue; } .icon { margin-right: 0.5rem; } .large { font-size: 2rem; }

D. .button { color: blue; } .button_icon { margin-right: 0.5rem; } .button_large { font-size: 2rem; }

Solution

1. Step 1: Understand & usage in nested selectors

   The & appends to the parent selector .button. So &__icon becomes .button__icon and &--large becomes .button--large.

2. Step 2: Write the generated CSS

   The CSS will have three selectors: .button, .button__icon, and .button--large with their respective styles.

3. Final Answer:

   .button { color: blue; } .button__icon { margin-right: 0.5rem; } .button--large { font-size: 2rem; } -> Option B

4. Quick Check:

   & + BEM = combined class names [OK]

Hint: &__element and &--modifier append to block class [OK]

Common Mistakes:

• Using underscore instead of double underscore for elements
• Not combining & with parent selector
• Leaving & in final CSS

4. Identify the error in this Sass code using BEM naming:

.menu {
  &__item {
    color: black;
  }
  &-active {
    font-weight: bold;
  }
}

medium

A. The modifier should use double dashes: &--active instead of &-active.

B. The element selector &__item is invalid and should be &-item.

C. The parent selector .menu is missing a dot.

D. The color property cannot be inside &__item.

Solution

1. Step 1: Check BEM modifier syntax

   Modifiers in BEM use double dashes --, so &-active is incorrect; it should be &--active.

2. Step 2: Verify element syntax

   &__item is correct for elements, so no error there.

3. Final Answer:

   The modifier should use double dashes: &--active instead of &-active. -> Option A

4. Quick Check:

   Modifier syntax = &--modifier [OK]

Hint: Modifiers always use double dashes -- not single [OK]

Common Mistakes:

• Using single dash for modifiers
• Confusing element and modifier syntax
• Thinking &__item is invalid

5. You want to style a BEM block .profile with an element avatar and a modifier highlighted. Which Sass code correctly combines & with BEM naming to style both the element and modifier inside .profile?

hard

A. .profile {
&__avatar {
border-radius: 50%;
}
&--highlighted {
background-color: yellow;
}
}

B. .profile {
&-avatar {
border-radius: 50%;
}
&-highlighted {
background-color: yellow;
}
}

C. .profile {
&__avatar {
border-radius: 50%;
}
&-highlighted {
background-color: yellow;
}
}

D. .profile {
&-avatar {
border-radius: 50%;
}
&--highlighted {
background-color: yellow;
}
}

Solution

1. Step 1: Apply BEM element syntax

   Elements use double underscore __, so &__avatar correctly targets .profile__avatar.

2. Step 2: Apply BEM modifier syntax

   Modifiers use double dash --, so &--highlighted correctly targets .profile--highlighted.

3. Step 3: Check other options

   Options A, C, and D use single dash for either element or modifier, which is incorrect in BEM.

4. Final Answer:

   .profile { &__avatar { border-radius: 50%; } &--highlighted { background-color: yellow; } } -> Option A

5. Quick Check:

   Element = &__element, Modifier = &--modifier [OK]

Hint: Use &__element and &--modifier exactly for BEM [OK]

Common Mistakes:

• Using single dash for elements or modifiers
• Mixing element and modifier syntax
• Not nesting inside the block selector