Syntax for if/else condition in SCSS mixin

Hi I'm trying to learn SASS/SCSS and am trying to refactor my own mixin for clearfix

what I'd like is for the mixin to be based on whether I pass the mixin a width.

thoughts so far (pseudo code only as I will be including other mixins)

@mixin clearfix($width) {

   @if !$width {

    // if width is not passed, or empty do this

   } @else {

        display: inline-block;
        width: $width;
   }
}

here's how I thought I might call it, but it's not working.

@include clearfix();

or

@include clearfix(100%)

or

@include clearfix(960px)

I'd ap开发者_运维问答preciate any help on the best or right way to do this!

You can assign default parameter values inline when you first create the mixin:

@mixin clearfix($width: 'auto') {

  @if $width == 'auto' {

    // if width is not passed, or empty do this

  } @else {

    display: inline-block;
    width: $width;

  }
}

You could try this:

$width:auto;
@mixin clearfix($width) {

   @if $width == 'auto' {

    // if width is not passed, or empty do this

   } @else {
        display: inline-block;
        width: $width;
   }
}

I'm not sure of your intended result, but setting a default value should return false.

You could default the parameter to null or false.
This way, it would be shorter to test if a value has been passed as parameter.

@mixin clearfix($width: null) {

  @if not ($width) {

    // if width is not passed, or empty do this

  } @else {

    display: inline-block;
    width: $width;

  }
}