FSCSS Variable Fallback Operator (||)

FSCSS Variable Fallback Operator (||)

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FSCSS Variable Fallback Operator (||)FSCSS tutorial

FSCSS v1.1.13 introduces a new feature: Variable Fallback Operator You can now define a...

FSCSS v1.1.13 introduces a new feature:

Variable Fallback Operator

You can now define a default value directly inside a variable declaration using:

property: $/variable || fallback;

FSCSS resolves the value in this order:
If the variable exists → use it
Otherwise → use the fallback value

Example

Component Definition

str(Button#1, "
background: $/bg || #06f;
color: $/color || #fff;
border: $/border || 2px solid;
padding: 10px;
border-radius: 20px;
")
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Usage

.btn {
  $bg: linear-gradient(40deg, #aaf, #000);
  $color: #020;
  Button#1
}
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If a variable is not provided, FSCSS automatically applies the fallback.

Why This Matters

The fallback operator makes components:

  • More reusable
  • Safer by default
  • Cleaner to maintain
  • Plugin-friendly

Plugin authors can now ship components that work even when users don’t define every variable.

Required Variables
You can still enforce strict variables:

If $bg! is marked required and missing, FSCSS will warn accordingly.

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