sass-mq-build

A simple Sass function to build media query strings that can be stored in variables, to be used with the native CSS @media (…) syntax.

This approach is inspired by the CSS Custom Media Queries proposal (which may or may not end up in Media Queries Level 5. It allows using this kind of syntax in Sass code:

$my-media-query: mq-build(30em, 60em);

@media ($my-media-query) {
  /* Nice CSS code */
}

which outputs:

@media (min-width: 30em) and (max-width: 59.99em) {
  /* Nice CSS code */
}

Features

• You can use @media instead of @include with a mixin, yay!
• Accepts any CSS length unit (px, em and more) for breakpoints.
• Can substract 1px or 0.01em from “max” values (max-width and max-height). This is helpful if you want to avoid situations were two conflicting media queries match because the window width (or height) is exactly at the provided dimension.
• Supports min-width, max-width, min-height, max-height, and passing other arbitrary queries as strings (e.g. "orientation: landscape"). This is limited but works for 99.9% of our needs (and actually we mostly use min-width/max-width and not much else).

For alternatives and/or bigger feature set, you might want to take a look at @include-media or Sass MQ.

Complete usage

The mq-build() function can particularly be useful if you’re using variables to store breakpoints, and want to create a set of variables for pre-built media queries.

@import "mq-build";

// Two breakpoints divide the possible widths in 3 groups
$start-medium: 750px;
$start-large: 1280px;

// Single-group queries
$mq-small:  mq-build($maxw: $start-medium);
$mq-medium: mq-build($minw: $start-medium, $maxw: $start-large);
$mq-large:  mq-build($minw: $start-large);

// Two-group queries
$mq-upto-medium: mq-build($maxw: $start-large);
$mq-from-medium: mq-build($minw: $start-medium;

Then in your CSS code…

.MyComponent {
  /* Common, mobile-first styles */
  @media ($mq-from-medium) {
    /* Styles for medium and large screens */
  }
  @media ($mq-large) {
    /* Large screens only */
  }
}

Note that you can always combine a custom media query (saved in a variable) with a literal one:

@media ($desktop) and (min-resolution: 2ddpx) {
  /* High resolution big screen */
}

Function parameters

All parameters are optional.

1. $minw - CSS length value for min-width
2. $maxw - CSS length value for max-width
3. $minh - CSS length value for min-height
4. $maxh - CSS length value for max-height
5. $other - (string or list of strings)
6. $wrap - whether to wrap the result in parentheses

If the resulting query has more than one condition, the and keyword is used. There is no support for or, not, etc.

Global options

$mq-build-wrap (defaults to false)

Should we add parentheses around the returned string? This is theoretically better, but it doesn’t work with the @media ($variable) syntax.

If you set this option to true, or pass mq-build(…, $wrap:true), you will have to use the generated string like this:

@media #{$variable} { … }

$mq-build-offset (defaults to true)

Whether to remove a small number from max-width and max-height queries, in order to avoid collisions. What collisions? Well, if you have this kind of code:

@media (min-width: 800px) {
    ...
}
@media (max-width: 800px) {
    ...
}

… then your intention was probably not to have both blocks of CSS apply at the same time. But if the window width is exactly 800px, both media queries will match, resulting in some style conflicts.

So our solution is to automatically output this code:

@media (min-width: 800px) {
    ...
}
@media (max-width: 799px) {
    ...
}