Including mixins with @include in SASS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a mixin in Sass?

A mixin is a reusable group of CSS styles that you can include in other selectors to avoid repeating code.

beginner

How do you include a mixin in Sass?

You use the @include directive followed by the mixin name and optional arguments.

beginner

Example: What does @include rounded-corners; do?

It inserts the styles defined inside the rounded-corners mixin into the current CSS rule.

intermediate

Can mixins accept parameters in Sass?

Yes, mixins can take parameters to customize the styles when included.

beginner

Why use @include instead of copying styles?

Using @include keeps your code DRY (Don't Repeat Yourself), easier to maintain, and reduces errors.

What does @include do in Sass?

A Inserts styles from a mixin into a selector

B Defines a new mixin

C Imports another Sass file

D Creates a CSS variable

@include inserts the styles from a previously defined mixin into the current CSS rule.

How do you pass a parameter to a mixin when using @include?

A @include mixin-name(parameter);

B @include mixin-name: parameter;

C @include mixin-name { parameter }

D @include mixin-name = parameter;

You pass parameters inside parentheses after the mixin name, like @include mixin-name(parameter);.

Which of these is the correct way to include a mixin named box-shadow?

A @import box-shadow;

B @mixin box-shadow;

C @include box-shadow;

D @use box-shadow;

@include box-shadow; is the correct syntax to include a mixin.

What is the main benefit of using mixins with @include?

A To repeat the same styles easily

B To write less CSS and keep code organized

C To create animations

D To link external CSS files

Mixins help write less CSS by reusing style blocks, keeping code clean and organized.

If a mixin has parameters, what happens if you don’t provide them when using @include?

A Sass throws an error

B The CSS breaks

C The mixin is ignored

D Default parameter values are used if defined

If default values are set for parameters, Sass uses them when you don’t provide arguments.

Explain how to create and use a mixin with @include in Sass.

Think about how to write reusable style blocks and then apply them.

Why is using @include with mixins better than copying CSS styles multiple times?

Consider the idea of writing once and using many times.

Practice

1. What does the @include directive do in Sass?

easy

A. It inserts the styles defined in a mixin into the current selector.

B. It defines a new mixin with reusable styles.

C. It imports another Sass file into the current file.

D. It creates a variable to store a color or value.

Solution

1. Step 1: Understand the role of @include

   The @include directive is used to add the styles from a mixin into a selector.

2. Step 2: Differentiate from other Sass features

   Defining mixins uses @mixin, importing files uses @import, and variables use $ syntax.

3. Final Answer:

   It inserts the styles defined in a mixin into the current selector. -> Option A

4. Quick Check:

   @include adds mixin styles [OK]

Hint: Remember: @include adds mixin styles inside selectors [OK]

Common Mistakes:

• Confusing @include with @mixin which defines mixins
• Thinking @include imports files
• Mixing up variables with mixins

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

easy

A. @include button-style();

B. @mixin button-style();

C. @include button-style;

D. @use button-style();

Solution

1. Step 1: Recall the syntax for including mixins

   The correct syntax to include a mixin is @include mixin-name(); with parentheses even if no arguments are passed.

2. Step 2: Eliminate incorrect options

   @mixin defines a mixin, not includes it. @use is for modules. Omitting parentheses is invalid syntax.

3. Final Answer:

   @include button-style(); -> Option A

4. Quick Check:

   Include mixin with @include name() [OK]

Hint: Use @include mixinName() with parentheses [OK]

Common Mistakes:

• Forgetting parentheses after mixin name
• Using @mixin instead of @include to call mixin
• Confusing @use with @include

3. Given the Sass code:

@mixin border-radius($radius) {
  border-radius: $radius;
}

.box {
  @include border-radius(10px);
  background: blue;
}

What CSS will this produce?

medium

A. .box { border-radius: 10; background: blue; }

B. .box { border-radius: $radius; background: blue; }

C. .box { border-radius: 10px; background: blue; }

D. .box { background: blue; }

Solution

1. Step 1: Understand mixin with argument

   The mixin border-radius takes a parameter $radius and sets border-radius to that value.

2. Step 2: Apply mixin with 10px argument

   Including @include border-radius(10px); replaces $radius with 10px in the output CSS.

3. Final Answer:

   .box { border-radius: 10px; background: blue; } -> Option C

4. Quick Check:

   Mixin argument replaces variable in output [OK]

Hint: Mixin arguments replace variables inside mixin [OK]

Common Mistakes:

• Leaving variable name $radius in output CSS
• Omitting units like px in argument
• Ignoring mixin styles in output

4. Identify the error in this Sass code:

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

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

medium

A. Cannot use @include inside a selector.

B. Mixin should be defined with parentheses even if no arguments.

C. Mixin name should start with $ sign.

D. Missing parentheses after mixin name in @include.

Solution

1. Step 1: Check @include syntax

   When including a mixin, parentheses are required even if no arguments are passed.

2. Step 2: Verify other parts

   Mixin definition without parentheses is allowed if no arguments. Mixin names do not start with $. @include is valid inside selectors.

3. Final Answer:

   Missing parentheses after mixin name in @include. -> Option D

4. Quick Check:

   @include needs parentheses even if empty [OK]

Hint: Always add () after mixin name in @include [OK]

Common Mistakes:

• Omitting parentheses in @include
• Thinking mixin names start with $
• Believing @include can't be inside selectors

5. You want to create a reusable mixin card that sets a white background, shadow, and border radius. You also want to customize the border radius when including it. Which Sass code correctly defines and uses this mixin?

hard

A. @mixin card {
background: white;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
border-radius: $radius;
}

.container {
@include card(1rem);
}

B. @mixin card($radius) {
background: white;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
border-radius: $radius;
}

.container {
@include card(1rem);
}

C. @mixin card($radius) {
background: white;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
border-radius: 1rem;
}

.container {
@include card;
}

D. @mixin card($radius) {
background: white;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
border-radius: $radius;
}

.container {
@include card;
}

Solution

1. Step 1: Define mixin with parameter for border radius

   The mixin card must accept $radius to customize border radius.

2. Step 2: Include mixin with argument

   When including, pass the desired radius value like @include card(1rem);.

3. Step 3: Check other options for errors

   @mixin card { background: white; box-shadow: 0 2px 5px rgba(0,0,0,0.1); border-radius: $radius; } .container { @include card(1rem); } uses $radius without parameter, causing error. @mixin card($radius) { background: white; box-shadow: 0 2px 5px rgba(0,0,0,0.1); border-radius: 1rem; } .container { @include card; } hardcodes radius and omits parentheses in include. @mixin card($radius) { background: white; box-shadow: 0 2px 5px rgba(0,0,0,0.1); border-radius: $radius; } .container { @include card; } omits argument when including.

4. Final Answer:

   @mixin card($radius) { background: white; box-shadow: 0 2px 5px rgba(0,0,0,0.1); border-radius: $radius; } .container { @include card(1rem); } -> Option B

5. Quick Check:

   Define mixin with param, include with argument [OK]

Hint: Define mixin params and pass args in @include [OK]

Common Mistakes:

• Using variables inside mixin without parameters
• Forgetting parentheses in @include
• Not passing required arguments when including