Difftastic Ruby

A Ruby interface and wrapper for the wonderful Difftastic CLI tool.

Creating a Differ

First, create a differ with your configuration:

MY_DIFFER = Difftastic::Differ.new(
  background: :dark,
  color: :always,
  left_label: "Expected",
  right_label: "Actual"
)

Diffing Objects

You can diff objects with different configurations:

a = { foo: 1, bar: [2, 3, 4] }
b = { foo: 1, bar: [2, 4, 3] }

puts MY_DIFFER.diff_objects(a, b)

Diffing Ruby Code

You can diff Ruby code:

a = <<~RUBY
  def hello
    puts "Hello, world!"
  end
RUBY

b = <<~RUBY
  def hello
    puts "Goodbye, world!"
  end
RUBY

puts MY_DIFFER.diff_ruby(a, b)

Additional File Type Methods

You can also diff other file types using the following methods:

a = "<html>\n\t<body>\n\t\t<h1>Hello, world!</h1>\n\t</body>\n</html>"
b = "<html>\n\t<body>\n\t\t<h1>Goodbye, world!</h1>\n\t</body>\n</html>"

puts MY_DIFFER.diff_html(a, b)

a = '{ "foo": 1, "bar": 2 }'
b = '{ "foo": 1, "bar": 3 }'

puts MY_DIFFER.diff_json(a, b)

a = "body { color: red; }"
b = "body { color: blue; }"

puts MY_DIFFER.diff_css(a, b)

a = "<note><to>Tove</to><from>Jani</from></note>"
b = "<note><to>Tove</to><from>John</from></note>"

puts MY_DIFFER.diff_xml(a, b)

a = "foo: 1\nbar: 2"
b = "foo: 1\nbar: 3"

puts MY_DIFFER.diff_yaml(a, b)

Configuring Difftastic::Differ

You can configure the Difftastic::Differ instance with various options:

background: Set the background color (:dark or :light).
color: Set the color mode (:always, :never, or :auto).
syntax_highlight: Enable or disable syntax highlighting (:on or :off).
context: Set the number of context lines to display.
width: Use this many columns when calculating line wrapping. If not specified, difftastic will detect the terminal width.
tab_width: Set the tab width for indentation.
parse_error_limit: Set the limit for parse errors.
underline_highlights: Enable or disable underlining highlights (true or false).
left_label: Set the label for the left side of the diff.
right_label: Set the label for the right side of the diff.
display: Set the display mode ("side-by-side-show-both", "side-by-side", or "inline").

Pretty Method

The Difftastic module includes a pretty method for formatting objects:

object = { foo: 1, bar: [2, 3, 4] }
formatted_object = Difftastic.pretty(object)
puts formatted_object

difftastic