USD currency formatting filter for Liquid templates

currency.rb

# Custom text filters
module TextFilter
  # USD Currency
  def currency(input)
    return sprintf('$%0.2f',input).gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")
  end
end
# Globally register custom text filters
Liquid::Template.register_filter(TextFilter)

# Test
@template = Liquid::Template.parse(" {{ 1000.009234 | currency }} ")
puts @template.render

sprintf magic stolen / borrowed from Mike Pence