foldkit-plus

Packages that extend a Foldkit application outward — to agents, servers, other devices, the URL, and design systems — without giving it a second place to keep state.

A Foldkit application is one state machine: a Schema-typed Model, a Message union naming everything that can happen, and one pure update function that turns a Message into the next Model and some Commands. That shape is easy to reason about, test, and replay. It gets lost the moment an app grows a cache in a hook, a store in the URL, a tool handler that re-implements a transition, or a sync layer with its own reducer.

Everything in this repository keeps the one state machine. An agent can only send Messages update already handles. Server data lives in the Model and is reconciled by update. Replicas replay the same Messages through the same update. The URL and local storage mirror a slice of the Model; they never own one. Views are styled from outside without forking. Each package answers one question, and they compose because they meet at explicit application boundaries.

The website: foldkit-plus.pages.dev has each package's guides and API reference, and the demos, each an example from this repository built as static files. Those with a server run it in your browser, shared by every tab, so nothing you do leaves it:

• A blog studio and its site (examples/cms): Drafts beside the row, revisions, scheduled publishing and a page builder, with the public site rendered at build time.
• Two devices, one registry (examples/registry): Two devices edit 10,000 products in a data grid, offline and in conflict, and agree once both are back.
• Pages two tabs edit at once (examples/pages): Rich text two people edit at the same time, online or not, converging through one journal.
• A rich text playground (examples/richtext-playground): One document with movable blocks, anchored discussions, images, tables, code, toggles and footnotes, every edit a transition of the Model.
• A todo list an agent can use (examples/todo-app): One application definition drives the view, the tools an agent calls, the document replicas share, and the policy the server enforces.
• A data grid over 100,000 rows (examples/data-grid): A grid that owns focus, selection, columns and the open editor, while the application owns every row.
• Eight widgets from shared primitives (examples/widgets): Once the capabilities exist, a family of widgets gets cheap: each one is a Bundle placement plus Behaviors on a shared Collection description, with no bespoke state machine.