CheckboxRef

Boolean toggle. Tab-owned: the browser holds the canonical checked state.

kind

input

defaults (class-level)

field	type	default	notes
`label`	`str`	`""`	text next to the box; empty means no label, box only.
`checked`	`bool`	`False`	initial checked state seeded on mount.

Class attributes on the python CheckboxRef. Shipped on mount under the field entry's props key and used to seed the slice. Later server -> tab writes override the slice value.

interactions

op	dir	payload	nu method	notes
`write`	server -> tab	`bool`	`store`	canonical push or reset; replaces the local checked state.
`read`	server -> tab	request `null`; resp `bool`	(via `aeval`)	request/response, correlated by `id`. resolves the live value.
`notify`	tab -> server	`null`	`changed`	emitted on every user toggle of the box or its label.

CheckboxRef.aeval ships a read via session.aread and returns the bool. CheckboxRef.store(value) compiles to write. CheckboxRef.changed() is the standard Changed subscription.

wire payloads

// mount field entry (inside the mount payload)
{"path": "HomePage.agree", "type": "CheckboxRef", "props": {"label": "I agree", "checked": false}}

// server pushes a value
{"op": "write",  "ref": "HomePage.agree", "payload": true}

// server fetches
{"op": "read",   "ref": "HomePage.agree", "payload": null, "id": "ab12"}
{"op": "read",   "ref": "HomePage.agree", "payload": true, "id": "ab12"}

// browser tells server the user toggled
{"op": "notify", "ref": "HomePage.agree", "payload": null}

write and read-response payloads are msgpack bools. notify and read-request payloads are msgpack nil.

renderer

web/src/refs/checkbox.tsx. Native <input type="checkbox"> wrapped in a <label> so the label text is also a click target. Tailwind utility classes; no shadcn dep.

slice shape

{
  type: "CheckboxRef",
  value: null,
  label: string,
  checked: boolean,
  write: (v: unknown) => void,
  get: () => boolean,
}

Seeded from field.props on mount. write coerces non-bool / nil payloads via Boolean(v). get reads the live slice to avoid stale closures.

edge cases

write payload is msgpack nil (Nu sentinel): coerced to false.
write payload is non-bool: Boolean(v) coercion; no error frame.
slot never written and no props on mount: slice defaults to checked=false, label="".
empty label: the trailing <span> is omitted; only the box is clickable.
no debounce: each user toggle emits one notify.