UML Classes

Basics

D2 fully supports UML Class diagrams. Here's a minimal example:

Each key of a class shape defines either a field or a method.

The value of a field key is its type.

Any key that contains ( is a method, whose value is the return type.

A method key without a value has a return type of void.

Escaping reserved keywords

If you'd like to use a reserved keyword, wrap it in quotes.

Visibilities

You can also use UML-style prefixes to indicate field/method visibility.

visibility prefix	meaning
none	public
+	public
-	private
#	protected

See https://www.uml-diagrams.org/visibility.html

Here's an example with differing visibilities and more complex types:

Full example