@each loop over maps in SASS - Mini Project: Build & Apply

@each Loop Over Maps in Sass

📖 Scenario: You are designing a simple website theme. You want to create CSS classes for different button colors using Sass. Each button color has a name and a hex color code.

🎯 Goal: Build a Sass stylesheet that uses an @each loop to create CSS classes for buttons with background colors from a map.

📋 What You'll Learn

Create a Sass map called $button-colors with three entries: primary with #3498db, secondary with #2ecc71, and danger with #e74c3c.

Create a variable $padding set to 1rem.

Use an @each loop to generate CSS classes named .btn-primary, .btn-secondary, and .btn-danger with the correct background colors and padding.

Add a final style rule for .btn that sets the text color to white and border radius to 0.25rem.

💡 Why This Matters

🌍 Real World

Using Sass maps and loops helps you write less code and keep your styles consistent when designing websites with multiple color themes.

💼 Career

Front-end developers often use Sass to manage complex styles efficiently, especially when working on large projects with many design variations.

1

Create the $button-colors map

Create a Sass map called $button-colors with these exact entries: primary: #3498db, secondary: #2ecc71, and danger: #e74c3c.

SASS

// Create the $button-colors map with the specified entries
// Your code here

Hint

Use parentheses ( ) to define a map in Sass. Separate entries with commas.

2

Add the $padding variable

Create a variable called $padding and set it to 1rem.

SASS

$button-colors: (
  primary: #3498db,
  secondary: #2ecc71,
  danger: #e74c3c
);

// Create the $padding variable and set it to 1rem
// Your code here

Hint

Variables in Sass start with $. Assign values with a colon and end with a semicolon.

3

Use @each loop to create button classes

Write an @each loop that iterates over $button-colors with variables $name and $color. Inside the loop, create CSS classes named .btn-#{$name} with background-color: $color and padding: $padding.

SASS

$button-colors: (
  primary: #3498db,
  secondary: #2ecc71,
  danger: #e74c3c
);

$padding: 1rem;

// Use @each loop to create button classes
// Your code here

Hint

Use @each $name, $color in $button-colors { ... } to loop over map entries. Use interpolation #{$name} to build class names.

4

Add the base .btn style

Add a CSS rule for the class .btn that sets color to white and border-radius to 0.25rem.

SASS

$button-colors: (
  primary: #3498db,
  secondary: #2ecc71,
  danger: #e74c3c
);

$padding: 1rem;

@each $name, $color in $button-colors {
  .btn-#{$name} {
    background-color: $color;
    padding: $padding;
  }
}

// Add .btn base style here
// Your code here

Hint

Write a normal CSS rule for .btn with the specified properties.

Practice

1. What does the @each loop do when used with a map in Sass?

easy

A. It creates a new map from the keys only.

B. It deletes all map entries after looping.

C. It repeats styles for each key-value pair in the map.

D. It converts the map into a list.

Solution

1. Step 1: Understand the purpose of @each with maps

   The @each loop iterates over each key-value pair in a map.

2. Step 2: Identify what happens during iteration

   For each pair, it repeats the block of styles or code inside the loop.

3. Final Answer:

   It repeats styles for each key-value pair in the map. -> Option C

4. Quick Check:

   @each loops over map pairs = repeats styles [OK]

Hint: Remember: @each repeats code for each map pair [OK]

Common Mistakes:

• Thinking @each deletes map entries
• Confusing map keys with list items
• Assuming it converts maps to lists

2. Which of the following is the correct syntax to loop over a map $colors with @each in Sass?

easy

A. @each $key $value in $colors { ... }

B. @each $colors in $key, $value { ... }

C. @each $value, $key in $colors { ... }

D. @each $key, $value in $colors { ... }

Solution

1. Step 1: Recall the correct @each syntax for maps

   The syntax requires two variables separated by a comma, then in, then the map name.

2. Step 2: Match the syntax to the options

   @each $key, $value in $colors { ... } correctly uses @each $key, $value in $colors. Others have wrong order or missing comma.

3. Final Answer:

   @each $key, $value in $colors { ... } -> Option D

4. Quick Check:

   Two variables separated by comma + in + map name [OK]

Hint: Use comma between key and value, then 'in' before map [OK]

Common Mistakes:

• Swapping key and value order
• Missing comma between variables
• Using wrong variable order or syntax

3. Given the Sass map and code:

$themes: (light: #fff, dark: #000); @each $name, $color in $themes { .#{$name}-theme { background: $color; } }

What CSS will this generate?

medium

A. .light-theme { background: #fff; } .dark-theme { background: #000; }

B. .light { background: #fff; } .dark { background: #000; }

C. .theme-light { background: #fff; } .theme-dark { background: #000; }

D. .light-theme { background: light; } .dark-theme { background: dark; }

Solution

1. Step 1: Understand the map and loop variables

   The map has keys light and dark with colors #fff and #000.

2. Step 2: Analyze the generated CSS selectors and properties

   The selector uses interpolation .#{$name}-theme producing .light-theme and .dark-theme. The background uses the color value.

3. Final Answer:

   .light-theme { background: #fff; } .dark-theme { background: #000; } -> Option A

4. Quick Check:

   Interpolation creates .light-theme and .dark-theme with correct colors [OK]

Hint: Interpolation with #{} creates dynamic class names [OK]

Common Mistakes:

• Forgetting interpolation syntax
• Using keys as colors instead of values
• Mixing up class name order

4. Identify the error in this Sass code:

$sizes: (small: 1rem, medium: 2rem); @each $size in $sizes { .btn-#{$size} { font-size: $size; } }

medium

A. Missing comma between key and value in @each loop.

B. Using only one variable for a map instead of two.

C. Incorrect interpolation syntax in class name.

D. Map keys and values are reversed.

Solution

1. Step 1: Check the @each loop variables

   The map has key-value pairs, so the loop needs two variables separated by a comma.

2. Step 2: Identify the problem with one variable

   The code uses only $size instead of $key, $value, so it cannot access both parts of the map.

3. Final Answer:

   Using only one variable for a map instead of two. -> Option B

4. Quick Check:

   Maps need two variables in @each loops [OK]

Hint: Use two variables for maps in @each loops [OK]

Common Mistakes:

• Using one variable for map iteration
• Forgetting comma between variables
• Misusing interpolation syntax

5. You have a Sass map:

$shadows: (none: 0 0 0 transparent, light: 0 1px 3px rgba(0,0,0,0.12), heavy: 0 4px 6px rgba(0,0,0,0.3));

Write a @each loop that creates classes .shadow-none, .shadow-light, and .shadow-heavy with the correct box-shadow property. Which code snippet is correct?

hard

A. @each $name, $shadow in $shadows { .shadow-#{$name} { box-shadow: $shadow; } }

B. @each $shadow, $name in $shadows { .shadow-#{$name} { box-shadow: $shadow; } }

C. @each $name in $shadows { .shadow-#{$name} { box-shadow: $name; } }

D. @each $name, $shadow in $shadows { .shadow-#{$shadow} { box-shadow: $name; } }

Solution

1. Step 1: Identify correct variable order for map iteration

   Maps use @each $key, $value in $map, so $name is key and $shadow is value.

2. Step 2: Check class name and property usage

   The class uses interpolation with the key $name, and the property uses the value $shadow.

3. Final Answer:

   @each $name, $shadow in $shadows { .shadow-#{$name} { box-shadow: $shadow; } } -> Option A

4. Quick Check:

   Key first, value second, use interpolation for class [OK]

Hint: Map loops: key first, value second, interpolate key for class [OK]

Common Mistakes:

• Swapping key and value variables
• Using only one variable for map
• Interpolating value instead of key in class name