:body was hardwired; now a TYPE declares which of its fields are compositions
({:name "body" :type "Composition"}), and an object may carry several (:body, :aside, :body-1).
The edit page renders ONE block editor per declared field (host/blog--block-editors →
host/blog--composition-fields → the type's Composition fields, default ["body"]); each editor
is independent, targets #comp-<field>, and its cards get field-qualified slugs
(<container>__<field>__<name>). Every block op takes a `field` (threaded via a hidden "field"
input, so routes are unchanged); the response re-renders just that field's editor.
STORAGE: compositions moved into a STRING-KEYED sub-dict :comps (like :field-values) —
string keys round-trip through persist cleanly, whereas a mix of a keyword :body and a string
"body" top-level key does NOT survive serialization as one key (it splits the data). body-of/
set-body! delegate to comp-of/set-comp! with "body" + a legacy top-level :body read fallback,
so existing bodies still render (the demos reseed into :comps on boot).
blog 174/174, full host conformance 403/403 (+ tests: a Landing type with two Composition
fields → two independent #comp-body/#comp-aside editors; block-add! to a named field; default
[body]). Editor still renders any node kind (no "unknown block"); #block-editor wrapper kept
so the Playwright selectors hold.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
giles
616c3cf966