PROTOCOL

WorkflowObserver

public protocol WorkflowObserver

The WorkflowObserver protocol provides an interface to receive updates during the runtime’s execution loop. All requirements are optional, and no-ops are provided by default.

Methods

sessionDidBegin(_:)

func sessionDidBegin(
    _ session: WorkflowSession
)

Indicates the start of a WorkflowSession, which tracks the life of the underlying WorkflowNode used to provide renderings for a given Workflow type and rendering key. - Parameter session: The WorkflowSession that began.

Parameters

Name	Description
session	The WorkflowSession that began.

sessionDidEnd(_:)

func sessionDidEnd(
    _ session: WorkflowSession
)

Marks the end of a WorkflowSession, indicating that the corresponding WorkflowNode has been removed from the tree of Workflows. - Parameter session: The WorkflowSession that ended.

Parameters

Name	Description
session	The WorkflowSession that ended.

workflowDidMakeInitialState(_:initialState:session:)

func workflowDidMakeInitialState<WorkflowType: Workflow>(
    _ workflow: WorkflowType,
    initialState: WorkflowType.State,
    session: WorkflowSession
)

Indicates a Workflow produced its initial state value. - Parameters: - workflow: The Workflow that just produced its initial state. - initialState: The State that was created. - session: The WorkflowSession corresponding to the backing WorkflowNode

Parameters

Name	Description
workflow	The Workflow that just produced its initial state.
initialState	The State that was created.
session	The WorkflowSession corresponding to the backing WorkflowNode

workflowWillRender(_:state:session:)

func workflowWillRender<WorkflowType: Workflow>(
    _ workflow: WorkflowType,
    state: WorkflowType.State,
    session: WorkflowSession
) -> ((WorkflowType.Rendering) -> Void)?

Called before a Workflow is queried for its latest Rendering. - Parameters: - workflow: The Workflow that is about to be render. - state: The corresponding State that will be used during the render call. - session: The WorkflowSession corresponding to the backing WorkflowNode. - Returns: An optional closure to be called immediately after the new Rendering is produced, which takes the rendering as the only parameter.

Parameters

Name	Description
workflow	The Workflow that is about to be render.
state	The corresponding State that will be used during the render call.
session	The WorkflowSession corresponding to the backing WorkflowNode.

workflowDidChange(from:to:state:session:)

func workflowDidChange<WorkflowType: Workflow>(
    from oldWorkflow: WorkflowType,
    to newWorkflow: WorkflowType,
    state: WorkflowType.State,
    session: WorkflowSession
)

Called after an existing Workflow is updated. - Parameters: - oldWorkflow: The previous Workflow - newWorkflow: The new Workflow - state: The state after the update has occurred. - session: The WorkflowSession corresponding to the backing WorkflowNode.

Parameters

Name	Description
oldWorkflow	The previous Workflow
newWorkflow	The new Workflow
state	The state the update has occurred.
session	The WorkflowSession corresponding to the backing WorkflowNode.

workflowDidReceiveAction(_:workflow:session:)

func workflowDidReceiveAction<Action: WorkflowAction>(
    _ action: Action,
    workflow: Action.WorkflowType,
    session: WorkflowSession
)

Called after a WorkflowAction is received, but before it has been handled and propagated up the tree. - Parameters: - action: The action that was received. - session: The WorkflowSession corresponding to the backing WorkflowNode.

Parameters

Name	Description
action	The action that was received.
session	The WorkflowSession corresponding to the backing WorkflowNode.

workflowWillApplyAction(_:workflow:state:session:)

func workflowWillApplyAction<Action: WorkflowAction>(
    _ action: Action,
    workflow: Action.WorkflowType,
    state: Action.WorkflowType.State,
    session: WorkflowSession
) -> ((Action.WorkflowType.State, Action.WorkflowType.Output?) -> Void)?

Called when a WorkflowAction will be applied to its corresponding Workflow’s State - Parameters: - action: The action that will be applied. - workflow: The action’s corresponding Workflow. - state: The state to which the action will be applied. - session: The WorkflowSession corresponding to the backing WorkflowNode. - Returns: An optional closure to be called immediately after the action is applied to the State, and an optional Output has been produced. The closure takes the updated state and optional output as its arguments.

Parameters

Name	Description
action	The action that will be applied.
workflow	The action’s corresponding Workflow.
state	The state to which the action will be applied.
session	The WorkflowSession corresponding to the backing WorkflowNode.