Generated by SassMeister.com.

input.sass

// MIXIN

=when($min: false, $max: false, $ie: false)
  
    @if $min and not($max)
        @media (min-width: $min)
            @content
      
    @if $max and not($min)
        @media (max-width: $max)
            @content

    @if $min and $max
        @media (min-width: $min) and (max-width: $max)
            @content
            
    @if $ie
        @content


// USAGE

.component

    +when($min: 21em)
      width: 100%

    +when($max: 48em)
        padding: 5%

    +when($min: 32em, $max: 48em)
        font-size: 2em

    +when($ie: true)
        color: red

output.css

.component {
  color: red;
}
@media (min-width: 21em) {
  .component {
    width: 100%;
  }
}
@media (max-width: 48em) {
  .component {
    padding: 5%;
  }
}
@media (min-width: 32em) and (max-width: 48em) {
  .component {
    font-size: 2em;
  }
}