sass-clamp

A responsive CSS clamp() utility for Sass that generates fluid typography and spacing with linear interpolation.

Installation

npm install sass-clamp

Usage

Requirements: This library requires Dart Sass. Node Sass is not supported.

Modern Dart Sass (≥1.71.0)

@use 'pkg:sass-clamp' as clamp;

.heading {
  font-size: clamp.fluid(16px, 24px, 320px, 1200px);
  // Output: clamp(16px, 13.09px + 0.91vw, 24px)
}

CLI compilation:

sass --pkg-importer=node style.scss output.css

Vite configuration:

// vite.config.js
import { defineConfig } from 'vite';
import { NodePackageImporter } from 'sass';

export default defineConfig({
  css: {
    preprocessorOptions: {
      scss: {
        pkgImporter: new NodePackageImporter(),
      },
    },
  },
});

Legacy Dart Sass (<1.71.0)

// Option 1: Use --load-path flag (recommended)
@use 'sass-clamp' as clamp;

// Option 2: Relative path from node_modules
@use './node_modules/sass-clamp' as clamp;

CLI compilation:

# Option 1: Using load-path
sass --load-path=./node_modules style.scss output.css

# Option 2: Direct compilation (relative paths)
sass style.scss output.css

Vite configuration:

// vite.config.js
import { defineConfig } from 'vite';

export default defineConfig({
  css: {
    preprocessorOptions: {
      scss: {
        // Add node_modules to include paths
        includePaths: ['node_modules'],
      },
    },
  },
});

Note: The pkg: syntax requires Dart Sass 1.71.0 or later and the --pkg-importer=node flag when using CLI. For older versions, use --load-path=./node_modules flag or relative paths.

API

fluid($min, $max, $min-vw, $max-vw, $base-font-size)

Generates a responsive clamp() function with linear interpolation.

Parameters:

• $min - Minimum value (px or rem)
• $max - Maximum value (px or rem)
• $min-vw - Minimum viewport width (px or rem)
• $max-vw - Maximum viewport width (px or rem)
• $base-font-size - Base font size for unit conversion (default: 16)

Returns:

• CSS clamp() function as a string

Example:

font-size: clamp.fluid(1rem, 1.5rem, 320px, 1200px);
// Returns: clamp(1rem, 0.82rem + 0.91vw, 1.5rem)

minmax($min, $max, $min-vw, $max-vw, $base-font-size)

Generates a responsive max(min()) function with linear interpolation for legacy browser compatibility.

Parameters:

• $min - Minimum value (px or rem)
• $max - Maximum value (px or rem)
• $min-vw - Minimum viewport width (px or rem)
• $max-vw - Maximum viewport width (px or rem)
• $base-font-size - Base font size for unit conversion (default: 16)

Returns:

• CSS max(min()) function as a string

Example:

font-size: clamp.minmax(1rem, 1.5rem, 320px, 1200px);
// Returns: max(1rem, min(0.82rem + 0.91vw, 1.5rem))

Use cases:

• Legacy browser support where clamp() is not available
• CSS-in-JS libraries with clamp() parsing issues
• Progressive enhancement scenarios

.heading {
  // Fallback for older browsers
  font-size: clamp.minmax(16px, 24px, 320px, 1200px);
  // Modern browsers
  font-size: clamp.fluid(16px, 24px, 320px, 1200px);
}

Min/Max Values

• Supports px or rem units
• One unit can be omitted (uses the other value's unit)
• Both values must use the same unit (when both are specified)

@use 'pkg:sass-clamp' as clamp; // or 'sass-clamp' for legacy

// Both units specified (must match)
.text-1 { font-size: clamp.fluid(16px, 24px, 320px, 1200px); }
.text-2 { font-size: clamp.fluid(1rem, 1.5rem, 20rem, 75rem); }

// One unit omitted (24 => 24px, 1 => 1rem)
.text-3 { font-size: clamp.fluid(16px, 24, 320px, 1200px); }
.text-4 { font-size: clamp.fluid(1, 1.5rem, 20rem, 75rem); }

Viewport Values

• Supports px or rem units
• One unit can be omitted (uses the other value's unit)
• Can mix px and rem units

// Mixed viewport units
.element {
  padding: clamp.fluid(16px, 32px, 20rem, 75rem);
}

Base Font Size ($base-font-size)

• Specify the pixel equivalent of 1rem (without unit)
• Used for px/rem conversions
• Can be set globally or per function call

// Global configuration
@use 'pkg:sass-clamp' as clamp with ( // or 'sass-clamp' for legacy
  $default-base-font-size: 18
);

// Per function call
.text {
  font-size: clamp.fluid(1rem, 1.5rem, 20rem, 75rem, 18);
}

Responsive Behavior

Growing with Viewport

// Font size grows as viewport expands
.heading {
  font-size: clamp.fluid(16px, 24px, 320px, 1200px);
}

Shrinking with Viewport

// Sidebar width shrinks as viewport grows (more space for content)
.sidebar {
  width: clamp.fluid(300px, 200px, 768px, 1920px);
}

// Font size decreases on larger screens
.dense-text {
  font-size: clamp.fluid(18px, 14px, 320px, 1200px);
}

Limitations

• Unitless values not supported: Properties like line-height, opacity, z-index that accept unitless values cannot be used with this function
• px/rem only: Only px and rem units are supported for each values

License

MIT