Struct ModuleInstance 

pub struct ModuleInstance {
    pub module: Module,
    pub mounted: bool,
    /* private fields */
}

A live module instance holding the current state and lifecycle callbacks.

State is wrapped in Arc for O(1) clone performance — critical because state is accessed on every render cycle. With Arc, “cloning” is just a reference count increment instead of a deep copy.

Lifecycle

new() → mount() → [update_state()...] → unmount()
         ↑                                    |
         └────────────────────────────────────┘
                  (can re-mount)

Mount/unmount are idempotent — calling mount() twice only fires on_created once.

Fields

module: Module

Module metadata (name, action names, state keys)

mounted: bool

Whether the module is currently mounted

Implementations

impl ModuleInstance

pub fn new(module: Module, initial_state: Value) -> Self

pub fn set_on_created<F>(&mut self, callback: F)

where F: Fn() + Send + Sync + 'static,

Set the on_created lifecycle callback

pub fn set_on_destroyed<F>(&mut self, callback: F)

where F: Fn() + Send + Sync + 'static,

Set the on_destroyed lifecycle callback

pub fn mount(&mut self)

Mount the module (call on_created)

pub fn unmount(&mut self)

Unmount the module (call on_destroyed)

pub fn update_state(&mut self, patch: Value)

Update state from a patch

Uses Arc::make_mut for copy-on-write semantics: if this is the only reference, mutates in place; otherwise clones first.

pub fn update_state_sparse(&mut self, paths: &[String], values: &Value)

Update state from sparse path-value pairs This is more efficient than sending the full state when only a few paths changed

Uses Arc::make_mut for copy-on-write semantics.

pub fn get_state(&self) -> &Value

Get a reference to the current state

For read-only access without cloning. Prefer this over get_state_shared() when you don’t need to store the state beyond the current scope.

pub fn get_state_shared(&self) -> Arc<Value>

Get a shared reference to the current state (O(1) clone)

Use this for the render hot path where state needs to be passed around without deep copying. Cloning the Arc is just a reference count increment.