API reference / @node-ts/bus-core / WorkflowMapper

Class: WorkflowMapper<WorkflowStateType, WorkflowType>

Defined in: packages/bus-core/src/workflow/workflow.ts:156

A workflow configuration that describes how to map incoming messages to handlers within the workflow.

Type Parameters

Type Parameter
WorkflowStateType extends WorkflowState
WorkflowType extends Workflow<WorkflowStateType>

Constructors

Constructor

new WorkflowMapper<WorkflowStateType, WorkflowType>(workflow): WorkflowMapper<WorkflowStateType, WorkflowType>;

Defined in: packages/bus-core/src/workflow/workflow.ts:170

Parameters

Parameter	Type
workflow	ClassConstructor<Workflow<WorkflowState>>

Returns

WorkflowMapper<WorkflowStateType, WorkflowType>

Properties

Property	Modifier	Type	Defined in
onStartedBy	readonly	Map<MessageDeclaration<Message>, { workflowCtor: ClassConstructor<Workflow<WorkflowState>>; workflowHandler: string; }>	packages/bus-core/src/workflow/workflow.ts:160
onWhen	readonly	Map<MessageDeclaration<Message>, OnWhenHandler>	packages/bus-core/src/workflow/workflow.ts:167

Accessors

workflowStateCtor

Get Signature

get workflowStateCtor(): 
  | ClassConstructor<WorkflowStateType>
  | undefined;

Defined in: packages/bus-core/src/workflow/workflow.ts:174

Returns

| ClassConstructor<WorkflowStateType> | undefined

Methods

startedBy()

startedBy<MessageType, THandlerName>(message, workflowHandler): this;

Defined in: packages/bus-core/src/workflow/workflow.ts:198

Starts a new instance of the workflow each time message is handled.

Messages are delivered at least once and starts aren't deduplicated, so a message that's retried after the new workflow state was saved (for example because another handler of the same message failed) starts a second workflow instance. Make the handler idempotent, such as by returning discardWorkflow() when a workflow already exists for the message, if that matters.

Type Parameters

Type Parameter
MessageType extends Message
THandlerName extends string

Parameters

Parameter	Type	Description
message	MessageDeclaration<MessageType>	The message that starts the workflow: a message class, or a definition from defineCommand or defineEvent
workflowHandler	WorkflowHandlerArgument<WorkflowType, THandlerName, MessageType, WorkflowStateType>	The name of the workflow method that handles message. It must take message and return changes to the workflow state, or nothing, with no fields that aren't in the state.

Returns

this

Throws

WorkflowAlreadyStartedByMessage if the workflow is already started by message

Example

mapper.withState(OrderState).startedBy(OrderPlaced, 'start')

---

when()

when<MessageType, THandlerName>(
   message, 
   workflowHandler, 
   customLookup?
): this;

Defined in: packages/bus-core/src/workflow/workflow.ts:231

Dispatches message to the workflow instances it maps to

Type Parameters

Type Parameter
MessageType extends Message
THandlerName extends string

Parameters

Parameter	Type	Description
message	MessageDeclaration<MessageType>	The message to handle: a message class, or a definition from defineCommand or defineEvent
workflowHandler	WorkflowHandlerArgument<WorkflowType, THandlerName, MessageType, WorkflowStateType>	The name of the workflow method that handles message. It must take message and return changes to the workflow state, or nothing, with no fields that aren't in the state.
customLookup?	MessageWorkflowMapping<MessageType, WorkflowStateType>	How to find the workflow instance for message. By default it's found by the workflowId sticky attribute that's added to messages sent from the workflow.

Returns

this

Throws

WorkflowAlreadyHandlesMessage if the workflow already handles message

Example

mapper.when(CardCharged, 'charged', { lookup: message => message.orderId, mapsTo: 'orderId' })

---

withState()

withState(workflowStateType): this;

Defined in: packages/bus-core/src/workflow/workflow.ts:178

Parameters

Parameter	Type
workflowStateType	ClassConstructor<WorkflowStateType>

Returns

this