Functions with parameters in SASS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a function with parameters in Sass?

A function with parameters in Sass is a reusable block of code that takes inputs (parameters) to perform calculations or return values based on those inputs.

beginner

How do you define a function with parameters in Sass?

Use <code>@function</code> followed by the function name and parentheses containing parameters. Example: <code>@function double($number) { @return $number * 2; }</code>

beginner

Why use parameters in Sass functions?

Parameters let you pass different values to the function each time you use it, making your code flexible and reusable.

beginner

What does this Sass function do?<br><pre>@function add($a, $b) { @return $a + $b; }</pre>

It takes two numbers, $a and $b, and returns their sum.

beginner

How do you call a Sass function with parameters?

Use the function name followed by parentheses with arguments. Example: width: add(10px, 5px); calls the add function with 10px and 5px.

How do you define a function with parameters in Sass?

A function name($param) { ... }

B @mixin name($param) { ... }

C def name($param) { ... }

D @function name($param) { ... }

In Sass, functions are defined using @function followed by the name and parameters in parentheses.

What does the parameter in a Sass function do?

A Imports another Sass file

B Stores a value passed to the function

C Creates a new CSS selector

D Defines a CSS property

Parameters hold values passed into the function to be used inside it.

What keyword returns a value from a Sass function?

A return

B yield

C @return

D output

Sass uses @return to send back a value from a function.

How do you call a function named 'multiply' with parameters 3 and 4 in Sass?

A multiply(3, 4)

B @include multiply(3, 4)

C multiply 3, 4

D @function multiply(3, 4)

Functions are called by their name with arguments in parentheses.

Which of these is NOT true about Sass functions with parameters?

A They create CSS selectors

B They can return values

C They can take multiple parameters

D They help reuse code

Functions do not create selectors; they return values for use in styles.

Explain how to create and use a function with parameters in Sass.

Think about how you pass ingredients to a recipe and get a dish back.

Why are parameters useful in Sass functions? Give an example.

Imagine a calculator that can add any two numbers you give it.

Practice

1. What is the main purpose of using @function with parameters in Sass?

easy

A. To define CSS classes with fixed styles

B. To import external CSS files

C. To create reusable code blocks that accept different inputs

D. To add comments inside Sass files

Solution

1. Step 1: Understand what @function does

   @function defines reusable code that can take inputs and return values.

2. Step 2: Identify the role of parameters

   Parameters allow the function to work with different values each time it is called.

3. Final Answer:

   To create reusable code blocks that accept different inputs -> Option C

4. Quick Check:

   Functions with parameters = reusable code with inputs [OK]

Hint: Functions reuse code by accepting inputs [OK]

Common Mistakes:

• Confusing functions with mixins
• Thinking functions define CSS classes
• Assuming functions import files

2. Which of the following is the correct syntax to define a Sass function named double that takes one parameter $n?

easy

A. @function double { $n -> $n * 2; }

B. function double($n) { return $n * 2; }

C. @mixin double($n) { @return $n * 2; }

D. @function double($n) { @return $n * 2; }

Solution

1. Step 1: Check the function keyword and parameter syntax

   The correct keyword is @function followed by the function name and parameters in parentheses.

2. Step 2: Verify the return statement

   The function must use @return to send back the result.

3. Final Answer:

   @function double($n) { @return $n * 2; } -> Option D

4. Quick Check:

   Correct function syntax uses @function and @return [OK]

Hint: Use @function and @return with parameters in parentheses [OK]

Common Mistakes:

• Using 'function' without @
• Mixing up mixins and functions
• Omitting @return keyword

3. What will be the output CSS of the following Sass code?

@function add($a, $b) { @return $a + $b; }
.box {
  width: add(10px, 5px);
}

medium

A. .box { width: 15px; }

B. .box { width: add(10px, 5px); }

C. .box { width: 10px + 5px; }

D. Syntax error due to missing semicolon

Solution

1. Step 1: Understand the function call

   The function add returns the sum of two values, here 10px + 5px = 15px.

2. Step 2: Check the output CSS

   The Sass compiler replaces the function call with the returned value, so width becomes 15px.

3. Final Answer:

   .box { width: 15px; } -> Option A

4. Quick Check:

   Function returns sum, output uses computed value [OK]

Hint: Functions return values replaced in CSS output [OK]

Common Mistakes:

• Expecting function name in output
• Thinking Sass outputs raw expressions
• Confusing mixin behavior with functions

4. Identify the error in this Sass function:

@function multiply($x, $y) {
  $result: $x * $y;
}

medium

A. Incorrect variable declaration syntax

B. Missing @return statement to output the result

C. Function name should be @mixin

D. Parameters must be declared without $

Solution

1. Step 1: Check function body for return

   The function assigns the product to a variable but does not return it.

2. Step 2: Understand function requirements

   Sass functions must use @return to send back a value; otherwise, they produce no output.

3. Final Answer:

   Missing @return statement to output the result -> Option B

4. Quick Check:

   Functions need @return to output values [OK]

Hint: Always use @return to output function results [OK]

Common Mistakes:

• Forgetting @return in functions
• Confusing mixins with functions
• Using variables without $

5. You want a Sass function responsive-size that takes a pixel value $px and returns a rem value assuming 16px base font size. Which function definition correctly achieves this?

hard

A. @function responsive-size($px) { @return $px / 16 * 1rem; }

B. @function responsive-size($px) { @return $px * 16rem; }

C. @function responsive-size($px) { @return $px + 16rem; }

D. @function responsive-size($px) { @return rem($px / 16); }

Solution

1. Step 1: Understand rem conversion

   To convert pixels to rem, divide the pixel value by the base font size (16).

2. Step 2: Write the correct return expression

   Multiply the division result by 1rem to get the rem unit value.

3. Step 3: Check each option

   @function responsive-size($px) { @return $px / 16 * 1rem; } correctly divides $px by 16 and multiplies by 1rem. Others either multiply incorrectly or use invalid functions.

4. Final Answer:

   @function responsive-size($px) { @return $px / 16 * 1rem; } -> Option A

5. Quick Check:

   Divide px by 16, multiply by 1rem for rem units [OK]

Hint: Divide px by 16 and multiply by 1rem for rem conversion [OK]

Common Mistakes:

• Multiplying px by 16 instead of dividing
• Adding units instead of multiplying
• Using undefined rem() function