ESS constructor pattern

constructor.ess

var bg = props.bg
var family = props.family

background = bg || 'white'
font-family = family || 'Arial'

output.css

.Foo {
  background: #fff
}

.Foo, .Bar {
  font-family: Arial
}

.Bar {
  background: purple
}

.Bazz {
  background: red;
  font-family: Helvetica;
}

test.ess

import Constructor from './constructor.ess?raw'

.Foo
  Constructor

.Bar
  Constructor(bg='purple')

.Bazz
  Constructor(bg='red' family='Helvetica')