The checkbox form field supports child fields.
import {Modal} from "@daypilot/modal"; // ... async function modalCheckbox() { const form = [ { name: "Name", id: "props.firstName" }, { name: "Specify last name", id: "enabled", type: "checkbox", children: [{ name: "Last name", id: "props.lastName" }], }, ]; const data = { enabled: true, props: { firstName: "John", lastName: "Doe", another: "field", }, }; const modal = await Modal.form(form, data); console.log(modal); }