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Composition

Build complex documents from smaller, reusable pieces. A component is a self-contained block of styles and content that any document — or other component — can drop in with use.

use is the same verb you already know from the canvas: a named component reference, optionally scoped with data and styled with style. Flow composition adds document concerns (config merge precedence); canvas composition adds geometry. One concept, two surfaces.

Why compose?​

  • Reuse — define a header, a cover page, or an appendix once; use it from every template
  • Separate concerns — a designer owns the letterhead component, an analyst owns the body
  • Iterate safely — update a component and every document that uses it picks up the change

Where use resolves​

use works anywhere content elements appear — the top-level content array, columns, table cells, list items, and header/footer content.

In this section​

  • Components — declare a reusable component with the "component" root key
  • Reusability — reference components with use, scope data, cascade styles, and merge configuration
  • Sections & Watermarks — assemble multi-section documents with per-section frames and watermarks
  • Nesting & Pipeline — recursion limits, safety guarantees, and how composition resolves