Useful Sass Mixins

mixins.scss

/// Responsive breakpoint manager
/// @access public
/// @param {String} $breakpoint - Breakpoint name
/// @requires $breakpoints
@mixin respond-to($breakpoint) {
  $raw-query: map-get($breakpoints, $breakpoint);

  @if $raw-query {
    $query: if(
      type-of($raw-query) == 'string',
      unquote($raw-query),
      inspect($raw-query)
    );

    @media #{$query} {
      @content;
    }
  } @else {
    @error 'No value found for `#{$breakpoint}`. '
         + 'Please make sure it is defined in `$breakpoints` map.';
  }
}

/// Calculate 'letter-spacing' from Photoshop value to ems
/// @access public
/// @param {Number} $value - Unitless letter spacing value 
@mixin letter-spacing($value: 0) {
  letter-spacing: ($value / 1000) * 1em;
}

/// Font smoothing
/// @access public
/// @param {Boolean} $bool - Boolean value
@mixin font-smoothing($bool: true) {
    @if $bool == true {
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
    } @else {
        -webkit-font-smoothing: subpixel-antialiased;
        -moz-osx-font-smoothing: auto;
    }
}