Variable interpolation with #{} in SASS - Practice Problems & Coding Challenges

Challenge - 5 Problems

📝 Syntax

intermediate

What is the output CSS of this Sass code using interpolation?

Given the Sass code below, what will be the compiled CSS output?

SASS

$color: red;

.button-#{$color} {
  background-color: $color;
}

A

.button-#color {
  background-color: red;
}

B

.button-#{$color} {
  background-color: red;
}

C

.button-red {
  background-color: $color;
}

D

.button-red {
  background-color: red;
}

💡 Hint

Interpolation replaces #{} with the variable's value inside selectors or property names.

The #{$color} inside the selector is replaced by the value of $color, which is 'red'. The property value uses $color directly, so it compiles to 'red'.

❓ rendering

intermediate

What color will the button have in the browser?

Consider this Sass code. What color will the button have when rendered in the browser?

SASS

$btn-color: blue;

.btn-#{$btn-color} {
  color: $btn-color;
}

A Green text color on the button

B No color applied, default text color

C Blue text color on the button

D Red text color on the button

💡 Hint

The variable $btn-color is set to blue and used both in selector and property.

The variable $btn-color is blue, so the selector becomes .btn-blue and the color property is blue, so the button text color is blue.

🧠 Conceptual

advanced

Why use #{} interpolation in Sass selectors?

Which reason best explains why #{} interpolation is used in Sass selectors?

A To import external CSS files

B To insert variable values dynamically into selectors or property names

C To create loops inside selectors

D To comment out code inside selectors

💡 Hint

Think about how variables can change parts of selectors.

Interpolation with #{} allows Sass to replace variables with their values inside selectors or property names, enabling dynamic CSS generation.

❓ selector

advanced

What selector does this Sass code produce?

Given the Sass code below, what is the exact CSS selector generated after compilation?

SASS

$state: active;

.menu-item-#{$state} {
  font-weight: bold;
}

A .menu-item-active

B .menu-item-#{$state}

C .menu-item-state

D .menu-item-$state

💡 Hint

Interpolation replaces #{$state} with the variable's value.

The variable $state is 'active', so the selector becomes '.menu-item-active'.

❓ accessibility

expert

How can interpolation help with accessible ARIA attributes in Sass?

You want to create multiple buttons with different ARIA labels using Sass variables and interpolation. Which Sass code correctly sets unique ARIA labels using interpolation?

A

$label: submit;
button[aria-label="#{$label}"] {
  background: green;
}

B

$label: submit;
button[aria-label=$label] {
  background: green;
}

C

$label: submit;
button[aria-label='label'] {
  background: green;
}

D

$label: submit;
button[aria-label=#{label}] {
  background: green;
}

💡 Hint

Attribute selectors need the variable value as a string inside quotes with interpolation.

Interpolation with #{} inside quotes inserts the variable value correctly in the attribute selector. Option A uses this correctly.