Roadmap

Pure host functions in reactive sites and callbacks

An opt-in meta: { pure: true } on a tool marks the host function as synchronous, deterministic and effect-free. Marked functions become callable in props, hidden, loading and each, and inside a callback such as rows.map(r => slugify(r.title)). Unmarked ones stay rejected there, as rows.map(r => deleteRow(r.id)) is today. A marked call can also be part of a larger expression: getUser({ id }).name.

Reusable expressions

A document names an expression once and refers to it from any seed or step. Today the same fetch is repeated in full at every call site.