Tutorials

Sass is-superselector() Function

Posted in Sass Tutorial

Updated on Sep 30, 2024

By Mari Selvan

👁️ 28 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

The is-superselector() function in Sass is a utility that helps developers determine whether one selector is a "superselector" of another.

In simpler terms, it checks if a selector matches all the elements that another selector matches, potentially even more.

This function is particularly useful for managing complex selector relationships and ensuring that your styles apply as intended.

💡 Syntax

The is-superselector() function is straightforward and takes two arguments:

Syntax

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is-superselector(superselector, subselector)

🔢 Parameters

superselector: A CSS selector that you want to test as the broader or more encompassing selector.
subselector: A CSS selector that you want to check if it's fully encompassed by the superselector.

↩️ Return Value

The function returns a Boolean value:

true: if the first selector (superselector) matches all the elements that the second selector (subselector) matches.
false: if the first selector does not match all elements of the second selector.

📝 Example Usage

Let's look at some practical examples to see how is-superselector() can be used to manage CSS selector relationships.

📜 Example 1: Basic Superselector Check

example.scss

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$super: '.button';
$sub: '.button.primary';

$check: is-superselector($super, $sub);

@if $check {
  // Code here executes because .button is a superselector of .button.primary
  .notification {
    color: green;
  }
}

In this example, .button is a superselector of .button.primary because .button.primary applies to a subset of elements matched by .button. Therefore, the function returns true.

📜 Example 2: Non-Superselector

example.scss

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$super: '.primary.button';
$sub: '.button.primary';

$check: is-superselector($super, $sub);

@if $check {
  .notification {
    color: green;
  }
} @else {
  .notification {
    color: red;
  }
}

In this case, .primary.button is not considered a superselector of .button.primary because of the order of the classes. Hence, the function returns false, and the alternative block of code executes.

📜 Example 3: Nested Selectors

example.scss

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$super: '.nav .item';
$sub: '.nav > .item';

$check: is-superselector($super, $sub);

@if $check {
  .notification {
    color: green;
  }
} @else {
  .notification {
    color: red;
  }
}

Here, .nav .item is not a superselector of .nav > .item because the latter is more specific about the direct child relationship. The function returns false.

🎉 Conclusion

The is-superselector() function in Sass is a handy tool for checking relationships between selectors, especially in complex stylesheets where inheritance and specificity are crucial. It enables you to programmatically manage selector logic, ensuring that your styles apply correctly without unintended consequences.

By using is-superselector(), you can write more maintainable, robust stylesheets and reduce the likelihood of selector conflicts. This function is particularly beneficial when working with large codebases or when integrating multiple CSS modules.