Mixin libraries pattern in SASS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a mixin named 'center' that centers content horizontally and vertically.

SASS

@mixin [1] {
  display: flex;
  justify-content: center;
  align-items: center;
}

Drag options to blanks, or click blank then click option'

Amiddle

Bflex-center

Calign

Dcenter

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-descriptive mixin name.

Forgetting to use '@mixin' keyword.

The mixin is named 'center' to clearly indicate its purpose of centering content.

2fill in blank

medium

Complete the code to include the 'center' mixin inside a CSS rule.

SASS

.box {
  width: 10rem;
  height: 10rem;
  background-color: lightblue;
  @include [1];
}

Drag options to blanks, or click blank then click option'

Aflex-center

Bcenter

Cmiddle

Dalign

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong mixin name.

Omitting the '@include' keyword.

To use a mixin, you write '@include' followed by the mixin's name, which is 'center' here.

3fill in blank

hard

Fix the error in the mixin definition by completing the missing keyword.

SASS

@[1] border-radius($radius) {
  border-radius: $radius;
}

Drag options to blanks, or click blank then click option'

Amixin

Binclude

Cdefine

Dfunction

Attempts:

3 left

💡 Hint

Common Mistakes

Using '@include' instead of '@mixin' to define.

Using 'function' keyword which is not valid in Sass.

The correct keyword to define a mixin is '@mixin'. The '@' is implied here, so 'mixin' is the keyword after '@'.

4fill in blank

hard

Fill both blanks to create a mixin that accepts a color and applies it as background and text color.

SASS

@mixin color-scheme($bg, $text) {
  background-color: [1];
  color: [2];
}

Drag options to blanks, or click blank then click option'

A$bg

B$text

Cbackground-color

Dcolor

Attempts:

3 left

💡 Hint

Common Mistakes

Using property names instead of variables.

Mixing up $bg and $text variables.

The mixin uses parameters $bg and $text. These variables are used to set background-color and color respectively.

5fill in blank

hard

Fill all three blanks to create a map of mixins and use a conditional to include one based on a variable.

SASS

$themes: (
  dark: [1],
  light: [2]
);

$selected-theme: dark;

@if map-has-key($themes, $selected-theme) {
  @include map-get($themes, [3]);
}

Drag options to blanks, or click blank then click option'

Adark-theme

Blight-theme

C$selected-theme

Dtheme

Attempts:

3 left

💡 Hint

Common Mistakes

Using string keys instead of mixin names in the map.

Using wrong variable to get the mixin.

The map keys are 'dark' and 'light' with mixin names 'dark-theme' and 'light-theme'. The variable $selected-theme is used to get the correct mixin.

Practice

1. What is the main purpose of using mixin libraries in Sass?

easy

A. To create HTML templates

B. To write plain CSS without variables

C. To compile Sass into JavaScript

D. To group reusable style blocks for consistent styling

Solution

1. Step 1: Understand mixins in Sass

   Mixins are reusable blocks of styles that help avoid repetition.

2. Step 2: Purpose of mixin libraries

   Mixin libraries group many mixins to keep styling consistent and reusable across projects.

3. Final Answer:

   To group reusable style blocks for consistent styling -> Option D

4. Quick Check:

   Mixin libraries = reusable style groups [OK]

Hint: Mixins group styles; libraries group mixins [OK]

Common Mistakes:

• Confusing mixins with plain CSS
• Thinking mixins create HTML
• Believing mixins compile to JavaScript

2. Which of the following is the correct syntax to include a mixin named button-style in Sass?

easy

A. @mixin button-style;

B. @include button-style;

C. include(button-style);

D. @use button-style;

Solution

1. Step 1: Recall mixin creation syntax

   Mixins are created with @mixin name { ... }.

2. Step 2: Recall mixin usage syntax

   To apply a mixin, use @include name;.

3. Final Answer:

   @include button-style; -> Option B

4. Quick Check:

   Use @include to apply mixins [OK]

Hint: Use @include to apply mixins, not @mixin [OK]

Common Mistakes:

• Using @mixin instead of @include to apply
• Writing include() like a function
• Confusing @use with @include

3. Given the Sass code:

@mixin card-style {
  border: 1px solid #ccc;
  padding: 1rem;
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

.card {
  @include card-style;
  background-color: white;
}

What CSS will be generated for the .card class?

medium

A. .card { border: 1px solid #ccc; padding: 1rem; box-shadow: 0 0 5px rgba(0,0,0,0.1); background-color: white; }

B. .card { @include card-style; background-color: white; }

C. .card { border: none; padding: 0; background-color: white; }

D. Syntax error, no CSS generated

Solution

1. Step 1: Understand mixin content

   The mixin card-style defines border, padding, and box-shadow styles.

2. Step 2: Applying mixin in .card

   Using @include card-style; inserts those styles inside .card, plus the background color.

3. Final Answer:

   .card { border: 1px solid #ccc; padding: 1rem; box-shadow: 0 0 5px rgba(0,0,0,0.1); background-color: white; } -> Option A

4. Quick Check:

   Mixin styles + extra styles = full CSS block [OK]

Hint: Mixin styles expand fully inside selector [OK]

Common Mistakes:

• Expecting @include to remain in CSS output
• Ignoring mixin styles when included
• Thinking mixins cause syntax errors

4. Identify the error in this Sass code snippet:

@mixin text-style {
  font-size: 1.2rem;
  color: #333;
}

.title {
  @mixin text-style;
  font-weight: bold;
}

medium

A. Missing semicolon after font-weight

B. Mixin name should be .text-style with dot

C. Using @mixin instead of @include inside .title

D. Cannot use mixins inside class selectors

Solution

1. Step 1: Check mixin usage syntax

   Mixins are created with @mixin but applied with @include.

2. Step 2: Identify incorrect usage

   The code uses @mixin text-style; inside .title, which is wrong syntax.

3. Final Answer:

   Using @mixin instead of @include inside .title -> Option C

4. Quick Check:

   Apply mixins with @include, not @mixin [OK]

Hint: Use @include to apply mixins, never @mixin [OK]

Common Mistakes:

• Confusing @mixin and @include
• Adding dot before mixin name
• Thinking mixins can't be used in selectors

5. You have a mixin library with multiple mixins for buttons. You want to create a new mixin primary-button that uses the existing button-base mixin and adds a blue background. Which Sass code correctly achieves this?

hard

A. @mixin primary-button { @include button-base; background-color: blue; }

B. @mixin primary-button { @mixin button-base; background-color: blue; }

C. @include primary-button { @include button-base; background-color: blue; }

D. @mixin primary-button { button-base(); background-color: blue; }

Solution

1. Step 1: Define new mixin with @mixin

   Use @mixin primary-button { ... } to create the new mixin.

2. Step 2: Include existing mixin inside new one

   Inside the new mixin, use @include button-base; to reuse styles.

3. Step 3: Add additional styles

   Add background-color: blue; after including the base mixin.

4. Final Answer:

   @mixin primary-button { @include button-base; background-color: blue; } -> Option A

5. Quick Check:

   New mixin includes old mixin + extra styles [OK]

Hint: Nest @include inside @mixin to combine styles [OK]

Common Mistakes:

• Using @mixin instead of @include inside mixin body
• Trying to call mixins like functions
• Using @include outside mixin definition incorrectly