Class State<Shape>

Live reactive accessor for state data. Deeply nested changes trigger automatic updates, including array, Map, and Set mutations.

The current state

Add a handler function for when this state changes.

Listeners are invoked in the order they are registered and are passed a reference to the internally managed state object as a readonly object.

Do not modify state values directly. Instead, use set or patch to make immutable updates.

Get a single value from the state object

The value is returned as Readonly to prevent accidental state mutations. To mutate stateful properties, use set or patch instead.

Apply complex updates to the state using a mutator function.

The mutator function takes one parameter which is a structuredClone copy of the current state object. Whatever is returned by the mutator is then patched in to the state.

Set multiple stateful properties at once, leaving omitted properties unchanged.

Remove a previously registered state handler

Fully replace the current state data and force an update

Set a single stateful property while leaving other properties unchanged.

Triggers an update to all listeners if the value is different from before when compared using shallow equality.

Returns a deep clone of the current state data using structuredClone() to make the copy.

The object returned from this function can be edited without modifying the actual internal state.

Copy