Intro to Composition

정보

This section's documentation is incomplete. We'll be adding more to this section soon.

D2 has built-in mechanisms for you to compose multiple boards into one diagram.

For example, this is a composition of 2 boards, exported as an animated SVG:

The way to define another board in a D2 diagram is to use 1 of 3 keywords. Each of these declare boards with different inheritance rules.

Keyword	Inheritance
layers	Boards which do not inherit. They are a new base.
scenarios	Boards which inherit from the base layer.
steps	Boards which inherit from the previous step.

Each one serves different use cases. The example above is achieved by defining a Scenario (the scenario of when we have to deploy a hotfix).

Thus far, all D2 diagrams we've encountered are single-board diagrams, the root board.

Composition in D2 is when you use one of those keywords to declare another board.

So now we have two boards: root and numbers. They cannot be visible at the same time of course, so exports have to accommodate these more dynamic diagrams, such as the animated SVG you see above.

Composition is one of D2's most powerful features, as you'll see from the use cases in this section.