Interface: WorkflowHandle<T>

client.WorkflowHandle

A client side handle to a single Workflow instance. It can be used to start, signal, query, wait for completion, terminate and cancel a Workflow execution.

Given the following Workflow definition:

export const incrementSignal = defineSignal('increment');
export const getValueQuery = defineQuery<number>('getValue');
export async function counterWorkflow(initialValue: number): Promise<void>;

Create a handle for running and interacting with a single Workflow:

const client = new WorkflowClient();
// Start the Workflow with initialValue of 2.
const handle = await client.start({
  workflowType: counterWorkflow,
  args: [2],
  taskQueue: 'tutorial',
});
await handle.signal(incrementSignal, 2);
await handle.query(getValueQuery); // 4
await handle.cancel();
await handle.result(); // throws WorkflowExecutionCancelledError

Type parameters

Name	Type
T	extends Workflow = Workflow

Hierarchy

• BaseWorkflowHandle<T>

  ↳ WorkflowHandle

  ↳↳ WorkflowHandleWithFirstExecutionRunId

  ↳↳ WorkflowHandleWithSignaledRunId

Properties

client

• Readonly client: WorkflowClient

Readonly accessor to the underlying WorkflowClient

---

workflowId

• Readonly workflowId: string

The workflowId of the current Workflow

Inherited from

BaseWorkflowHandle.workflowId

Methods

cancel

▸ cancel(): Promise<IRequestCancelWorkflowExecutionResponse>

Cancel a running Workflow.

When a Workflow is cancelled, the root scope throws CancelledFailure with message: 'Workflow canceled'. That means that all cancellable scopes will throw CancelledFailure.

Cancellation may be propagated to Activities depending on ActivityOptions#cancellationType, after which Activity calls may throw an ActivityFailure, and isCancellation(error) will be true (see isCancellation).

Cancellation may be propagated to Child Workflows depending on ChildWorkflowOptions#cancellationType, after which calls to executeChild and ChildWorkflowHandle#result will throw, and isCancellation(error) will be true (see isCancellation).

Returns

Promise<IRequestCancelWorkflowExecutionResponse>

---

describe

▸ describe(): Promise<WorkflowExecutionDescription>

Describe the current workflow execution

Returns

Promise<WorkflowExecutionDescription>

---

fetchHistory

▸ fetchHistory(): Promise<IHistory>

Return a workflow execution's history

Returns

Promise<IHistory>

---

query

▸ query<Ret, Args>(def, ...args): Promise<Ret>

Query a running or completed Workflow.

Example

await handle.query(getValueQuery);
await handle.query<number, []>('getValue');

Type parameters

Name	Type
Ret	Ret
Args	extends any[] = []

Parameters

Name	Type	Description
def	string | QueryDefinition<Ret, Args, string>	a query definition as returned from defineQuery or query name (string)
...args	Args	-

Returns

Promise<Ret>

---

result

▸ result(): Promise<WorkflowResultType<T>>

Promise that resolves when Workflow execution completes

Returns

Promise<WorkflowResultType<T>>

Inherited from

BaseWorkflowHandle.result

---

signal

▸ signal<Args, Name>(def, ...args): Promise<void>

Signal a running Workflow.

Example

await handle.signal(incrementSignal, 3);

Type parameters

Name	Type
Args	extends any[] = []
Name	extends string = string

Parameters

Name	Type	Description
def	string | SignalDefinition<Args, Name>	a signal definition as returned from defineSignal
...args	Args	-

Returns

Promise<void>

Inherited from

BaseWorkflowHandle.signal

---

terminate

▸ terminate(reason?): Promise<ITerminateWorkflowExecutionResponse>

Terminate a running Workflow

Parameters

Name	Type
reason?	string

Returns

Promise<ITerminateWorkflowExecutionResponse>