Copyright	(C) 2016-2026 David M. Johnson
License	BSD3-style (see the file LICENSE)
Maintainer	David M. Johnson <code@dmj.io>
Stability	experimental
Portability	non-portable
Safe Haskell	None
Language	Haskell2010

Miso.Runtime.Internal

Description

Overview

Miso.Runtime.Internal is a testing-only facade that re-exports the miso runtime's global mutable state from Miso.Runtime.

Do not import this module in application code. Mutating any of the exported IORef values will corrupt the component lifecycle and produce undefined behaviour. The module exists solely to give the miso-tests integration-test package direct access to component state for assertions.

Exported names

components — global IORef mapping ComponentId to ComponentState for every mounted component.
componentIds — monotonically increasing IORef used to assign fresh component identifiers.
rootComponentId — the well-known identifier of the top-level app component.
ComponentState — record holding the live model, scheduler mailbox, and other per-component runtime fields.
schedulerThread — IORef holding the ThreadId of the event-loop scheduler thread.

Documentation

components :: IORef (IntMap (ComponentState parent props model action)) Source #

componentMap

This is a global Component Map that holds the state of all currently mounted Components

componentIds :: IORef Int Source #

The global store of ComponentId, for internal-use only.

Used internally freshComponentId to allocate new ComponentId on mount.

rootComponentId :: ComponentId Source #

This is used to demarcate the ROOT of a page. This ID will *never* exist in the components map.

data ComponentState parent props model action Source #

Component state, data associated with the lifetime of a Component

Constructors

ComponentState

Fields

_componentId :: ComponentId
The ID of the current Component
_componentKey :: Maybe Key
Optional key for stable hot-reload model recovery
_componentParentId :: ComponentId
The ID of the Component's parent
_componentProps :: props
The current props passed to this Component
_prevComponentProps :: props
The previous Component props passed to this Component
_componentSubThreads :: IORef (Map MisoString ThreadId)
Mapping of all Sub in use by Component
_componentDOMRef :: DOMRef
The DOM reference the Component is mounted on
_componentVTree :: IORef VTree
A reference to the current virtual DOM (i.e. VTree)
_componentSink :: action -> IO ()
Component Sink used to enter events into the system
_componentModel :: model
Component state
_componentIsDirty :: Bool
Indicator if Component needs to be drawn
_componentScripts :: [DOMRef]
DOM references for <script> and <style> appended to <head>
_componentEvents :: Events
List of events a Component listens on
_componentBindings :: [Binding parent model]
Declarative bindings between Component model.
_componentMailbox :: Value -> Maybe action
Mailbox for asynchronous Component communication
_componentDraw :: model -> IO ()
Helper function for Component rendering
_componentPropsPhase :: props -> props -> IO ()
Helper function for Component props changed phase.
_componentModelDirty :: model -> model -> Bool
Model diffing
_componentApplyActions :: Seq action -> model -> IntMap (ComponentState parent props model action) -> props -> (IntMap (ComponentState parent props model action), model, [Schedule action], ComponentIds)
Component actions application
_componentTopics :: Map MisoString (Value -> IO ())
Component topics using for Pub Sub async communication.
_componentChildren :: ComponentIds
IntSet of children ComponentId

schedulerThread :: IORef ThreadId Source #

Global variable to hold the scheduler thread

N.B. undefined is safe here, it will always get populated. Also, we use this in cleanup when interactive mode (GHCi) is detected in that circumstance schedulerThread will always be populated. It's an invariant.

Overview

Exported names

See also

Documentation