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---
title: Advanced Event Handling
description: Master complex event patterns and middleware with Workflows
---
This guide explores advanced event handling techniques and patterns you can use with Workflows to build more sophisticated patterns.
## Event Composition
Workflows allow you to work with different event types and compose them in powerful ways:
### Multiple Event Types
You can define multiple event types for different kinds of data flowing through your workflow:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
// Define different event types
const textEvent = workflowEvent<string>();
const numberEvent = workflowEvent<number>();
const booleanEvent = workflowEvent<boolean>();
const complexEvent = workflowEvent<{ id: string; value: number }>();
// Create a workflow that can process different event types
const workflow = createWorkflow();
// Handle text events
workflow.handle([textEvent], (event) => {
console.log(`Processing text: ${event.data}`);
return numberEvent.with(event.data.length);
});
// Handle number events
workflow.handle([numberEvent], (event) => {
const isEven = event.data % 2 === 0;
console.log(`Number ${event.data} is ${isEven ? 'even' : 'odd'}`);
return booleanEvent.with(isEven);
});
// Handle boolean events
workflow.handle([booleanEvent], (event) => {
return complexEvent.with({
id: crypto.randomUUID(),
value: event.data ? 100 : 0
});
});
```
### Event Branching and Merging
You can create complex event flows with branching and merging patterns:
```ts
import { createWorkflow, workflowEvent, until, collect } from "llamaindex";
// Define events for a data processing pipeline
const inputEvent = workflowEvent<string>();
const validateEvent = workflowEvent<string>();
const processEvent = workflowEvent<string>();
const errorEvent = workflowEvent<Error>();
const resultEvent = workflowEvent<string>();
const completeEvent = workflowEvent<string[]>();
// Create workflow
const workflow = createWorkflow();
// Branch based on input validation
workflow.handle([inputEvent], (event) => {
if (event.data && event.data.trim().length > 0) {
return validateEvent.with(event.data.trim());
} else {
return errorEvent.with(new Error("Empty input"));
}
});
// Process valid inputs
workflow.handle([validateEvent], (event) => {
return processEvent.with(event.data.toUpperCase());
});
// Handle processing
workflow.handle([processEvent], (event) => {
return resultEvent.with(`Processed: ${event.data}`);
});
// Handle errors
workflow.handle([errorEvent], (event) => {
return resultEvent.with(`Error: ${event.data.message}`);
});
// Merge results: collect multiple results into a single completion event
workflow.handle([inputEvent], (start) => {
const { sendEvent, stream } = getContext();
// Process all inputs
const inputs = start.data.split(',').map(s => s.trim());
inputs.forEach(input => sendEvent(inputEvent.with(input)));
// Collect all results
const results = await collect(
until(stream, result => resultEvent.include(result))
.filter(ev => resultEvent.include(ev))
.take(inputs.length)
);
return completeEvent.with(results.map(r => r.data));
});
```
## Event Filtering and Transformation
You can filter and transform events to build sophisticated data processing pipelines:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
// Define events
const dataEvent = workflowEvent<number>();
const evenEvent = workflowEvent<number>();
const oddEvent = workflowEvent<number>();
const transformedEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string[]>();
// Create workflow
const workflow = createWorkflow();
// Filter even numbers
workflow.handle([dataEvent], (event) => {
if (event.data % 2 === 0) {
return evenEvent.with(event.data);
} else {
return oddEvent.with(event.data);
}
});
// Transform even numbers
workflow.handle([evenEvent], (event) => {
return transformedEvent.with(`Even: ${event.data}`);
});
// Transform odd numbers
workflow.handle([oddEvent], (event) => {
return transformedEvent.with(`Odd: ${event.data}`);
});
// Collect and organize results
workflow.handle([dataEvent], (start) => {
const { sendEvent, stream } = getContext();
// Generate a sequence of numbers
for (let i = 1; i <= 10; i++) {
sendEvent(dataEvent.with(i));
}
// Collect transformed events
const results = await collect(
until(stream)
.filter(ev => transformedEvent.include(ev))
.take(10)
);
return resultEvent.with(results.map(r => r.data));
});
```
## Working with `withTraceEvents` Middleware
The `withTraceEvents` middleware adds powerful tracing capabilities to your workflows:
```ts
import {
createWorkflow,
workflowEvent,
withTraceEvents,
runOnce,
createHandlerDecorator
} from "llamaindex";
// Define events
const startEvent = workflowEvent<string>();
const processEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string>();
// Create workflow with tracing
const workflow = withTraceEvents(createWorkflow());
// Create a custom handler decorator that logs execution time
const measureTime = createHandlerDecorator({
debugLabel: "measureTime",
getInitialValue: () => performance.now(),
onBeforeHandler: (handler, context, startTime) => {
console.log(`Starting handler execution at ${new Date().toISOString()}`);
return handler;
},
onAfterHandler: (result, context, startTime) => {
const duration = performance.now() - startTime;
console.log(`Handler executed in ${duration.toFixed(2)}ms`);
return startTime; // Return the initial value for next execution
}
});
// Run a specific handler only once
workflow.handle(
[startEvent],
runOnce((event) => {
console.log("This handler will only run once per workflow context");
return processEvent.with(event.data);
})
);
// Measure the execution time of this handler
workflow.handle(
[processEvent],
measureTime((event) => {
// Simulate processing time
const start = Date.now();
while (Date.now() - start < 100) {
// Busy wait for 100ms
}
return resultEvent.with(`Processed: ${event.data}`);
})
);
```
### Debugging with Substreams
You can use the `substream` feature to debug specific event flows:
```ts
import { createWorkflow, workflowEvent, withTraceEvents } from "llamaindex";
// Define events
const queryEvent = workflowEvent<string>();
const fetchEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string>();
// Create workflow with tracing
const workflow = withTraceEvents(createWorkflow());
// Query handler
workflow.handle([queryEvent], (event) => {
const { sendEvent, stream } = getContext();
// Create a specific fetch event for this query
const fetchInstance = fetchEvent.with(event.data);
sendEvent(fetchInstance);
// Create a substream to only track events related to this fetch
const substream = workflow.substream(fetchInstance, stream);
// Listen for results in the substream
(async () => {
for await (const event of substream) {
console.log(`Event in substream: ${event.type}`);
}
})();
return resultEvent.with(`Querying: ${event.data}`);
});
// Fetch handler
workflow.handle([fetchEvent], (event) => {
console.log(`Fetching data for: ${event.data}`);
// Actual fetch logic would go here
return resultEvent.with(`Results for: ${event.data}`);
});
```
## Advanced Validation and Type Safety
The `withValidation` middleware ensures your workflow connections are both type-safe and runtime-safe:
```ts
import { createWorkflow, workflowEvent, withValidation } from "llamaindex";
// Define events with explicit types
const inputEvent = workflowEvent<string, "input">();
const validateEvent = workflowEvent<string, "validate">();
const processEvent = workflowEvent<string, "process">();
const resultEvent = workflowEvent<string, "result">();
const errorEvent = workflowEvent<Error, "error">({
debugLabel: "errorEvent" // Add debug labels for better error messages
});
// Define the allowed event flow paths
const workflow = withValidation(
createWorkflow(),
[
[[inputEvent], [validateEvent, errorEvent]], // inputEvent can lead to validateEvent or errorEvent
[[validateEvent], [processEvent, errorEvent]], // validateEvent can lead to processEvent or errorEvent
[[processEvent], [resultEvent, errorEvent]], // processEvent can lead to resultEvent or errorEvent
[[errorEvent], [resultEvent]] // errorEvent can lead to resultEvent
]
);
// Now use strictHandle to get compile-time validation
workflow.strictHandle([inputEvent], (sendEvent, event) => {
try {
if (!event.data || event.data.trim().length === 0) {
throw new Error("Empty input");
}
// This is allowed by our validation rules
sendEvent(validateEvent.with(event.data.trim()));
// This would cause a compile-time error:
// sendEvent(resultEvent.with("Result")); // ❌ Not allowed by validation rules
} catch (err) {
// This is allowed by our validation rules
sendEvent(errorEvent.with(err instanceof Error ? err : new Error(String(err))));
}
});
// The rest of the workflow with strict validation
workflow.strictHandle([validateEvent], (sendEvent, event) => {
// Validation logic here
sendEvent(processEvent.with(event.data));
});
workflow.strictHandle([processEvent], (sendEvent, event) => {
// Processing logic here
sendEvent(resultEvent.with(`Processed: ${event.data}`));
});
workflow.strictHandle([errorEvent], (sendEvent, event) => {
// Error handling logic here
sendEvent(resultEvent.with(`Error handled: ${event.data.message}`));
});
```
## Creating Custom Middleware
You can create your own middleware to extend the workflow capabilities:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
// Create a logging middleware
function withLogging(workflow) {
const originalHandle = workflow.handle;
workflow.handle = function(eventTypes, handler) {
return originalHandle.call(workflow, eventTypes, async function(...args) {
const eventType = eventTypes.map(e => e.name || 'AnonymousEvent').join(',');
console.log(`[${new Date().toISOString()}] Handling ${eventType}`);
try {
const result = await handler(...args);
console.log(`[${new Date().toISOString()}] Completed ${eventType}`);
return result;
} catch (error) {
console.error(`[${new Date().toISOString()}] Error in ${eventType}:`, error);
throw error;
}
});
};
return workflow;
}
// Create a retry middleware
function withRetry(maxRetries = 3, workflow) {
const originalHandle = workflow.handle;
workflow.handle = function(eventTypes, handler) {
return originalHandle.call(workflow, eventTypes, async function(...args) {
let lastError;
for (let attempt = 1; attempt <= maxRetries; attempt++) {
try {
return await handler(...args);
} catch (error) {
lastError = error;
console.warn(`Attempt ${attempt}/${maxRetries} failed:`, error);
if (attempt < maxRetries) {
// Exponential backoff
await new Promise(resolve =>
setTimeout(resolve, Math.pow(2, attempt - 1) * 100)
);
}
}
}
throw lastError;
});
};
return workflow;
}
// Use the custom middleware
const workflow = withRetry(3, withLogging(createWorkflow()));
// Define events
const startEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string>();
// Add handlers
workflow.handle([startEvent], (event) => {
// This handler might fail but will be retried
if (Math.random() < 0.7) {
throw new Error("Random failure");
}
return resultEvent.with(`Processed: ${event.data}`);
});
```
## Integrating with External Systems
You can extend your workflows to integrate with external systems:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
// Define events
const fetchEvent = workflowEvent<string>();
const successEvent = workflowEvent<any>();
const failureEvent = workflowEvent<Error>();
// Create workflow
const workflow = createWorkflow();
// Handle external API calls with proper error handling
workflow.handle([fetchEvent], async (event) => {
const { signal } = getContext();
try {
// Use AbortSignal for cancellation support
const response = await fetch(event.data, { signal });
if (!response.ok) {
throw new Error(`HTTP error: ${response.status}`);
}
const data = await response.json();
return successEvent.with(data);
} catch (error) {
if (error.name === 'AbortError') {
return failureEvent.with(new Error('Request was aborted'));
}
return failureEvent.with(error instanceof Error ? error : new Error(String(error)));
}
});
// Database integration example
const dbQueryEvent = workflowEvent<{ collection: string; query: any }>();
const dbResultEvent = workflowEvent<any[]>();
workflow.handle([dbQueryEvent], async (event) => {
// Connect to database (pseudo-code)
const db = await connectToDatabase();
try {
const results = await db.collection(event.data.collection)
.find(event.data.query)
.toArray();
return dbResultEvent.with(results);
} catch (error) {
return failureEvent.with(error);
} finally {
await db.close();
}
});
```
## Handling Complex Asynchronous Patterns
LlamaIndex workflows excel at managing complex asynchronous patterns:
```ts
import { createWorkflow, workflowEvent, until, collect } from "llamaindex";
// Events for an orchestration workflow
const orchestrateEvent = workflowEvent<string[]>();
const taskEvent = workflowEvent<string>();
const progressEvent = workflowEvent<{ task: string; progress: number }>();
const taskCompleteEvent = workflowEvent<string>();
const aggregateEvent = workflowEvent<any>();
// Create workflow
const workflow = createWorkflow();
// Orchestrator: distribute tasks and collect results
workflow.handle([orchestrateEvent], async (event) => {
const { sendEvent, stream } = getContext();
const tasks = event.data;
// Start all tasks
tasks.forEach(task => sendEvent(taskEvent.with(task)));
// Track progress
let completed = 0;
const results = {};
// Process task completion and progress events
for await (const event of until(stream, () => completed === tasks.length)) {
if (progressEvent.include(event)) {
console.log(`Task ${event.data.task}: ${event.data.progress}%`);
} else if (taskCompleteEvent.include(event)) {
completed++;
results[event.data] = `Completed ${event.data}`;
console.log(`Completed ${completed}/${tasks.length} tasks`);
}
}
return aggregateEvent.with(results);
});
// Task processor
workflow.handle([taskEvent], async (event) => {
const { sendEvent } = getContext();
const task = event.data;
// Simulate task processing with progress updates
for (let progress = 0; progress <= 100; progress += 20) {
sendEvent(progressEvent.with({ task, progress }));
await new Promise(resolve => setTimeout(resolve, 200));
}
return taskCompleteEvent.with(task);
});
```
## Next Steps
Now that you've explored advanced event handling with workflows, you're ready to build sophisticated applications:
- [Integrating Workflows with other LlamaIndex Features](./llamaindex-integration.mdx)
@@ -0,0 +1,263 @@
---
title: Basic Workflow Patterns
description: Learn common patterns and techniques for building effective workflows
---
This guide explores common patterns you can use to build more complex workflows with workflows.
## Fan-out (Parallelism)
One of the most powerful features of workflows is the ability to run tasks in parallel:
```ts
import { createWorkflow, workflowEvent, until, collect } from "llamaindex";
// Define events
const startEvent = workflowEvent<string>();
const processItemEvent = workflowEvent<number>();
const resultEvent = workflowEvent<string>();
const completeEvent = workflowEvent<string[]>();
// Create workflow
const workflow = createWorkflow();
// Process start event: fan out to multiple processItemEvent events
workflow.handle([startEvent], (start) => {
const { sendEvent, stream } = getContext();
// Emit multiple events to be processed in parallel
for (let i = 0; i < 10; i++) {
sendEvent(processItemEvent.with(i));
}
// Collect all resultEvents and emit a final completeEvent
let condition = false;
const results = collect(
until(stream, () => condition)
.filter((ev) => resultEvent.includes(ev))
);
return completeEvent.with(results.map(event => event.data));
});
// Process each item
workflow.handle([processItemEvent], (event) => {
// Process the item
const processedValue = `Processed: ${event.data}`;
// If this is the last item, set the condition to stop collecting
if (event.data === 9) {
condition = true;
}
return resultEvent.with(processedValue);
});
```
This pattern allows you to:
1. Emit multiple events to be processed in parallel
2. Collect results as they come in
3. Complete once all parallel tasks are finished
## Conditional Branching
You can implement conditional logic in your workflows:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
const inputEvent = workflowEvent<number>();
const evenNumberEvent = workflowEvent<string>();
const oddNumberEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string>();
const workflow = createWorkflow();
// Branch based on whether the number is even or odd
workflow.handle([inputEvent], (event) => {
if (event.data % 2 === 0) {
return evenNumberEvent.with(`${event.data} is even`);
} else {
return oddNumberEvent.with(`${event.data} is odd`);
}
});
// Handle even numbers
workflow.handle([evenNumberEvent], (event) => {
return resultEvent.with(`Even result: ${event.data}`);
});
// Handle odd numbers
workflow.handle([oddNumberEvent], (event) => {
return resultEvent.with(`Odd result: ${event.data}`);
});
```
## Using Middleware
LlamaIndex workflows provide middleware that can enhance your workflows:
### `withStore` Middleware
The `withStore` middleware adds a persistent store to your workflow context:
```ts
import { createWorkflow, workflowEvent, withStore } from "llamaindex";
const startEvent = workflowEvent<void>();
const incrementEvent = workflowEvent<number>();
const resultEvent = workflowEvent<number>();
// Create a workflow with store middleware
const workflow = withStore(
() => ({
count: 0,
history: [] as number[],
}),
createWorkflow()
);
// Increment the counter
workflow.handle([startEvent], () => {
const store = workflow.getStore();
store.count += 1;
store.history.push(store.count);
return incrementEvent.with(store.count);
});
// Return the current count
workflow.handle([incrementEvent], (event) => {
const store = workflow.getStore();
return resultEvent.with(store.count);
});
```
### `withValidation` Middleware
The `withValidation` middleware adds compile-time and runtime validation to your workflows:
```ts
import { createWorkflow, workflowEvent, withValidation } from "llamaindex";
const startEvent = workflowEvent<string, "start">();
const processEvent = workflowEvent<number, "process">();
const resultEvent = workflowEvent<string, "result">();
const disallowedEvent = workflowEvent<void, "disallowed">();
// Create a workflow with validation middleware
// Define allowed event paths
const workflow = withValidation(
createWorkflow(),
[
[[startEvent], [processEvent]], // startEvent can only lead to processEvent
[[processEvent], [resultEvent]], // processEvent can only lead to resultEvent
]
);
// This will pass validation
workflow.strictHandle([startEvent], (sendEvent, start) => {
sendEvent(processEvent.with(123)); // ✅ This is allowed
});
// This would fail at compile time and runtime
workflow.strictHandle([startEvent], (sendEvent, start) => {
// sendEvent(disallowedEvent.with()); // ❌ This would cause an error
// sendEvent(resultEvent.with("result")); // ❌ This would also cause an error
});
```
## Error Handling
LlamaIndex workflows provide built-in mechanisms for handling errors:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
const startEvent = workflowEvent<string>();
const processEvent = workflowEvent<number>();
const errorEvent = workflowEvent<Error>();
const resultEvent = workflowEvent<string>();
const workflow = createWorkflow();
workflow.handle([startEvent], (start) => {
try {
const num = Number.parseInt(start.data, 10);
if (isNaN(num)) {
throw new Error("Invalid number");
}
return processEvent.with(num);
} catch (err) {
return errorEvent.with(err instanceof Error ? err : new Error(String(err)));
}
});
workflow.handle([processEvent], (event) => {
return resultEvent.with(`Result: ${event.data * 2}`);
});
workflow.handle([errorEvent], (event) => {
return resultEvent.with(`Error: ${event.data.message}`);
});
```
You can also use the signal in `getContext()` to handle errors:
```ts
workflow.handle([processEvent], () => {
const { signal } = getContext();
signal.onabort = () => {
console.error("Process aborted:", signal.reason);
// Clean up resources
};
// Your processing logic here
});
```
## Connecting with Server Endpoints
Workflow can be used as middleware in server frameworks like Express, Hono, or Fastify:
```ts
import { Hono } from "hono";
import { serve } from "@hono/node-server";
import { createWorkflow, workflowEvent, createHonoHandler } from "llamaindex";
// Define events
const queryEvent = workflowEvent<string>();
const responseEvent = workflowEvent<string>();
// Create workflow
const workflow = createWorkflow();
workflow.handle([queryEvent], (event) => {
const response = `Processed: ${event.data}`;
return responseEvent.with(response);
});
// Create Hono app
const app = new Hono();
// Set up workflow endpoint
app.post(
"/workflow",
createHonoHandler(
workflow,
async (ctx) => queryEvent.with(await ctx.req.text()),
responseEvent
)
);
// Start server
serve(app, ({ port }) => {
console.log(`Server started at http://localhost:${port}`);
});
```
## Next Steps
Now that you've learned about basic workflow patterns, explore more advanced topics:
- [Streaming with Workflows](./streaming.mdx)
- [Advanced Event Handling](./advanced-events.mdx)
@@ -1,8 +1,18 @@
---
title: Inputs / Outputs
description: Learn how to use different inputs and outputs in your workflows.
title: Inputs / Outputs (Outdated)
description: This page has been replaced with newer documentation
---
# ⚠️ Outdated Documentation
This documentation is for an older version of the workflow API. Please refer to the new llama-flow documentation:
- [Getting Started with llama-flow](./index.mdx)
- [Basic Workflow Patterns](./basic-workflow.mdx)
- [Advanced Event Handling](./advanced-events.mdx)
The new API provides a more lightweight and flexible approach to building workflows.
Inputs and outputs are the way to communicate between steps in a workflow. In the previous example,
we used `StartEvent` and `StopEvent` to communicate between steps. However, you can use any type of event to communicate between steps.
@@ -1,196 +1,111 @@
---
title: Basic Usage
description: Learn how to use the LlamaIndex workflow.
title: Getting Started with Workflows
description: Learn how to use LlamaIndex's lightweight workflow engine for TypeScript
---
A `Workflow` in LlamaIndex.TS is an event-driven abstraction used to chain together several events.
Workflows are made up of steps, with each step responsible for handling certain event types and emitting new events.
Workflows are a simple and lightweight engine for TypeScript. Built with ❤️ by LlamaIndex.
Workflows are designed for any cases that benefit from event-driven programming, not only for LLM and AI tasks.
- Minimal core API (\<\=2kb)
- 100% Type safe
- Event-driven, stream oriented programming
- Support for multiple JS runtimes/frameworks
```package-install
npm i @llamaindex/workflow
## Installation
It's directly included with the `llamaindex` package:
```shell
npm i llamaindex
```
## Start from scratch
Let's start from a Hello World workflow.
```ts twoslash
import { Workflow } from '@llamaindex/workflow';
type ContextData = {
counter: number;
}
// ---cut---
const contextData: ContextData = { counter: 0 };
const workflow = new Workflow<ContextData, string, string>();
// ^?
But can also be installed separately:
```shell
npm i @llama-flow/core
# or with yarn
yarn add @llama-flow/core
# or with pnpm
pnpm add @llama-flow/core
```
First, we define a workflow with 3 generic types: `ContextData`, `Input`, and `Output`.
## Key Concepts
In general, `ContextData` is used to store the shared data between steps, `Input` is the type of the input event, and `Output` is the type of the output event.
- **Events**: Data carriers that flow through the workflow
- **Handlers**: Functions that process events and emit new events
- **Workflow**: Connects events and handlers together
- **Context**: Runtime environment for a workflow execution
In you code logic, you should **share state between steps via `ContextData`**.
## Basic Usage
```ts twoslash
import { Workflow, StartEvent, StopEvent } from '@llamaindex/workflow';
Let's build a simple workflow that processes a text input:
type ContextData = {
counter: number;
}
### 1. Define events
const contextData: ContextData = { counter: 0 };
First, we need to define the events that will flow through our workflow:
const workflow = new Workflow<ContextData, string, string>();
// ---cut---
workflow.addStep({
inputs: [StartEvent<string>],
outputs: [StopEvent<string>]
}, async (context, startEvent) => {
const input = startEvent.data;
context.data.counter++;
return new StopEvent(`Hello, ${input}!`);
```ts
import { workflowEvent } from "llamaindex";
// Define input and output events
const startEvent = workflowEvent<string>(); // Takes a string input
const convertEvent = workflowEvent<Number>(); // Intermediate event
const stopEvent = workflowEvent<1 | -1>(); // Final output event, returns 1 or -1
```
### 2. Create a workflow and connect events
Next, we'll create our workflow and define how events are processed:
```ts
import { createWorkflow } from "llamaindex";
const workflow = createWorkflow();
// Handle the start event: convert the string to a number
workflow.handle([startEvent], (start) => {
return convertEvent.with(Number.parseInt(start.data, 10));
});
// Handle the convert event: determine if number is positive or negative
workflow.handle([convertEvent], (convert) => {
return stopEvent.with(convert.data > 0 ? 1 : -1);
});
```
In the workflow, we add a step that listens to `StartEvent<string>` and emits `StopEvent<string>`.
### 3. Run the workflow
The step is an async function that takes two arguments: `context` and `event`.
Finally, we can execute our workflow:
### `context` type
```ts
// Create a workflow context and send the initial event
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with("42"));
<AutoTypeTable path="./src/deps/type.ts" name="HandlerContext" />
// Process the stream to get the result
import { pipeline } from "node:stream/promises";
There are two more properties in `HandlerContext`:
- `sendEvent`: invoke another event in the workflow, other than `StartEvent`, `StopEvent`, or the current event. (Or there will have circular reference)
- `requireEvent`: wait for a specific event to be emitted.
You can use `sendEvent` and `requireEvent` to build complex workflows.
```ts twoslash
import { Workflow, StartEvent, StopEvent, WorkflowEvent } from '@llamaindex/workflow';
type ContextData = {
counter: number;
}
const contextData: ContextData = { counter: 0 };
const workflow = new Workflow<ContextData, string, string>();
// ---cut---
class AnalysisStartEvent extends WorkflowEvent<string> {}
class AnalysisStopEvent extends WorkflowEvent<boolean> {}
workflow.addStep({
inputs: [AnalysisStartEvent],
outputs: [AnalysisStopEvent]
}, async (...args) => {
// do some analysis
return new AnalysisStopEvent(true);
})
workflow.addStep({
inputs: [StartEvent<string>],
outputs: [StopEvent<string>]
}, async (context, startEvent) => {
const input = startEvent.data;
context.sendEvent(new AnalysisStartEvent('start'));
context.data.counter++;
const { data } = await context.requireEvent(AnalysisStopEvent);
return new StopEvent(`Hello, ${input}! Analysis result: ${data ? 'success' : 'fail'}`);
});
```
For example, you can compile `requireEvent` with `waitUntil` in [Vercel Functions](https://vercel.com/docs/functions/functions-api-reference#waituntil) or [Cloudflare Worker](https://developers.cloudflare.com/workers/runtime-apis/context/#waituntil)
```ts twoslash
import { waitUntil } from '@vercel/functions';
import { Workflow, StartEvent, StopEvent, WorkflowEvent } from '@llamaindex/workflow';
type ContextData = {
counter: number;
}
const contextData: ContextData = { counter: 0 };
const workflow = new Workflow<ContextData, string, string>();
class AnalysisStartEvent extends WorkflowEvent<string> {}
class AnalysisStopEvent extends WorkflowEvent<boolean> {}
// ---cut---
workflow.addStep({
inputs: [StartEvent<string>],
outputs: [StopEvent<string>]
}, async (context, startEvent) => {
const input = startEvent.data;
context.sendEvent(new AnalysisStartEvent('start'));
context.data.counter++;
waitUntil(context.requireEvent(AnalysisStopEvent));
// note that `waitUntil` is not a promise, it will extend the lifetime of the workflow
// you can wait for some background tasks to finish
return new StopEvent(`Hello, ${input}!`);
});
```
## Multiple runs
You can run the same workflow multiple times with different inputs.
```ts twoslash
import { Workflow, StartEvent, StopEvent } from '@llamaindex/workflow';
type ContextData = {
counter: number;
}
const contextData: ContextData = { counter: 0 };
const workflow = new Workflow<ContextData, string, string>();
workflow.addStep({
inputs: [StartEvent<string>],
outputs: [StopEvent<string>]
}, async (context, startEvent) => {
const input = startEvent.data;
context.data.counter++;
return new StopEvent(`Hello, ${input}!`);
const result = await pipeline(stream, async function (source) {
for await (const event of source) {
if (stopEvent.include(event)) {
return `Result: ${event.data === 1 ? 'positive' : 'negative'}`;
}
}
});
// ---cut---
{
const ret = await workflow.run('Alex', contextData);
console.log(ret.data); // Hello, Alex!
}
{
const ret = await workflow.run('World', contextData);
console.log(ret.data); // Hello, World!
}
console.log(result); // "Result: positive"
```
Context is shared between runs, so the counter will be increased.
Or using the stream utilities:
Ideally, it should be serializable to make sure it can be recovered from HTTP requests or other storage.
```ts
import { collect, until } from "llamaindex";
### Full example
// Collect all events until we get a stopEvent
const allEvents = await collect(until(stream, stopEvent));
const finalEvent = allEvents[allEvents.length - 1];
console.log(`Result: ${finalEvent.data === 1 ? 'positive' : 'negative'}`);
```
<iframe
className="w-full h-[440px]"
aria-label="Workflow example"
src="https://stackblitz.com/github/run-llama/LlamaIndexTS/tree/main/examples?file=node/workflow/basic.ts"
/>
## `Workflow` type
<AutoTypeTable path="./src/deps/type.ts" name="Workflow" />
## `WorkflowContext` type
<AutoTypeTable path="./src/deps/type.ts" name="WorkflowContext" />
Ready to learn more? Check out our [detailed examples](./basic-workflow.mdx) to see llama-flow in action!
@@ -0,0 +1,288 @@
---
title: Integrating with LlamaIndex
description: Build AI applications by combining Workflows with other LlamaIndex features
---
This guide demonstrates how to combine the power of the workflow engine with LlamaIndex's retrieval and reasoning capabilities to build sophisticated AI applications.
## Basic RAG Workflow
Let's build a simple Retrieval-Augmented Generation (RAG) workflow:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
import { Document, serviceContextFromDefaults, VectorStoreIndex } from "llamaindex";
import { OpenAI, OpenAIEmbedding } from "@llamaindex/openai";
import { Settings } from "@llamaindex/core/global"
// Define events
const queryEvent = workflowEvent<string>();
const retrieveEvent = workflowEvent<{ query: string; documents: Document[] }>();
const generateEvent = workflowEvent<{ query: string; context: string }>();
const responseEvent = workflowEvent<string>();
// Create workflow
const workflow = createWorkflow();
// Set default global llm
Settings.llm = new OpenAI({
model: "gpt-4.1-mini",
temperature: 0.2
});
// Set the default global embedModel
Settings.embedModel = new OpenAIEmbedding({
model: "text-embedding-3-small",
});
// Sample documents
const documents = [
new Document({
text: "LlamaIndex is a data framework for LLM applications to ingest, structure, and access private or domain-specific data.",
}),
new Document({
text: "LlamaIndex workflows are a lightweight workflow engine for TypeScript, designed to create event-driven processes.",
}),
];
// Create vector store index
const index = await VectorStoreIndex.fromDocuments(documents);
// Handle query: Retrieve relevant documents
workflow.handle([queryEvent], (event) => {
const query = event.data;
console.log(`Processing query: ${query}`);
// Retrieve relevant documents
const retriever = index.asRetriever();
const nodes = retriever.retrieve(query);
return retrieveEvent.with({
query,
documents: nodes.map(node => node.node),
});
});
// Handle retrieval results: Generate response
workflow.handle([retrieveEvent], async (event) => {
const { query, documents } = event.data;
// Combine document content as context
const context = documents.map(doc => doc.text).join('\n\n');
return generateEvent.with({ query, context });
});
// Handle generation: Produce final response
workflow.handle([generateEvent], async (event) => {
const { query, context } = event.data;
// Create a prompt with the context and query
const prompt = `
Context information:
${context}
Based on the context information and no other knowledge, answer the following query:
${query}
`;
// Generate response with LLM
const response = await Settings.llm.complete({ prompt });
return responseEvent.with(response.text);
});
// Execute the workflow
const { stream, sendEvent } = workflow.createContext();
sendEvent(queryEvent.with("What is LlamaIndex?"));
// Process the stream
for await (const event of stream) {
if (responseEvent.include(event)) {
console.log("Final response:", event.data);
break;
}
}
```
## Building a Chat Application
Let's create a more complex chat application that maintains conversation history:
```ts
import { createWorkflow, workflowEvent, withStore } from "llamaindex";
import { OpenAI, OpenAIEmbedding } from "@llamaindex/openai";
import { Document, serviceContextFromDefaults, VectorStoreIndex } from "llamaindex";
import { Settings } from "@llamaindex/core/global"
// Set default global llm
Settings.llm = new OpenAI({
model: "gpt-4.1-mini",
temperature: 0.2
});
// Set the default global embedModel
Settings.embedModel = new OpenAIEmbedding({
model: "text-embedding-3-small",
});
// Define store type
type ChatStore = {
history: Array<{ role: string; content: string }>;
documents: Document[];
index: VectorStoreIndex | null;
};
// Define events
const initEvent = workflowEvent<Document[]>();
const indexCreatedEvent = workflowEvent<VectorStoreIndex>();
const userMessageEvent = workflowEvent<string>();
const retrievalEvent = workflowEvent<{ query: string; nodes: any[] }>();
const responseEvent = workflowEvent<{ message: { content: string } }>();
// Create workflow with store
const workflow = withStore<ChatStore>(
() => ({
history: [],
documents: [],
index: null,
}),
createWorkflow()
);
// Initialize the chat context
workflow.handle([initEvent], async (event) => {
const store = workflow.getStore();
store.documents = event.data;
// Create index from documents
const index = await VectorStoreIndex.fromDocuments(store.documents);
store.index = index;
return indexCreatedEvent.with(index);
});
// Process user message
workflow.handle([userMessageEvent], (event) => {
const userMessage = event.data;
const store = workflow.getStore();
// Add user message to history
store.history.push({
role: "user",
content: userMessage,
});
if (!store.index) {
throw new Error("Index not initialized yet");
}
// Retrieve relevant context
const retriever = store.index.asRetriever();
const nodes = retriever.retrieve(userMessage);
return retrievalEvent.with({
query: userMessage,
nodes,
});
});
// Generate response from retrieval results
workflow.handle([retrievalEvent], async (event) => {
const { query, nodes } = event.data;
const store = workflow.getStore();
// Context from retrieved nodes
const context = nodes.map(node => node.node.text).join('\n\n');
// Create the system message with context
const systemMessage = {
role: "system",
content: `You are a helpful assistant. Use the following information to answer the user's question:
${context}
Only use the information provided above to answer. If you don't know, say so.`,
};
// Create full conversation history for the chat
const messages = [
systemMessage,
...store.history,
];
// Generate response
const response = await Settings.llm.chat({
messages,
});
// Add assistant response to history
store.history.push({
role: "assistant",
content: response.message.content,
});
return responseEvent.with(response);
});
// Example usage
async function runChat() {
// Sample documents
const documents = [
new Document({
text: "LlamaIndex is a data framework for LLM applications to ingest, structure, and access private or domain-specific data.",
}),
new Document({
text: "LlamaIndex Workflows are a lightweight workflow engine for TypeScript, designed to create event-driven processes.",
}),
];
// Initialize the chat
const { stream, sendEvent } = workflow.createContext();
sendEvent(initEvent.with(documents));
// Wait for index creation
for await (const event of stream) {
if (indexCreatedEvent.include(event)) {
console.log("Index created successfully");
break;
}
}
// Start conversation
async function sendUserMessage(message: string) {
sendEvent(userMessageEvent.with(message));
for await (const event of stream) {
if (responseEvent.include(event)) {
console.log("Assistant:", event.data.message.content);
return event.data.message.content;
}
}
}
await sendUserMessage("What is LlamaIndex?");
await sendUserMessage("Can you tell me about LlamaIndex workflows?");
await sendUserMessage("How might these two technologies work together?");
}
runChat();
```
## Building an Tool Calling Agent
[TODO]
## Conclusion
By combining the lightweight, event-driven workflow engine with LlamaIndex's powerful document indexing and querying capabilities, you can build sophisticated AI applications with clean, maintainable code.
The event-driven architecture allows you to:
1. Break complex processes into manageable steps
2. Create reusable components for common AI workflows
3. Easily debug and monitor each phase of execution
4. Scale your applications by isolating resource-intensive steps
5. Build more resilient systems with better error handling
As you build your own applications, consider how the patterns shown here can be adapted to your specific use cases.
@@ -1,6 +1,12 @@
{
"title": "Workflow",
"description": "See how to use @llamaindex/workflow",
"title": "Workflows",
"description": "Event-driven workflow engine for TypeScript",
"defaultOpen": false,
"pages": ["index", "different-inputs-outputs", "streaming"]
"pages": [
"index",
"basic-workflow",
"streaming",
"advanced-events",
"llamaindex-integration"
]
}
@@ -1,198 +1,371 @@
---
title: Streaming
description: Learn how to use the LlamaIndex workflow with streaming.
title: Streaming with Workflows
description: Learn how to build streaming workflows
---
`Workflow` API by default is designed for streaming data. In this guide, we will show you how to use the `Workflow` API with streaming data.
LlamaIndex workflows are designed from the ground up to work with streaming data. The streaming capabilities make it perfect for:
Each `workflow.run` call returns `WorkflowContext`, which implements `AsyncIterable` interface. You can use it to stream data.
- Building real-time applications
- Handling large datasets incrementally
- Creating responsive UIs that update as data becomes available
- Implementing long-running tasks with partial results
```ts twoslash
import { Workflow, WorkflowEvent, StartEvent, StopEvent } from '@llamaindex/workflow';
class ComputeEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
## Basic Streaming
Every workflow context provides a stream of events:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
// Define events
const startEvent = workflowEvent<string>();
const intermediateEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string>();
// Create workflow
const workflow = createWorkflow();
workflow.handle([startEvent], (event) => {
const { sendEvent } = getContext();
// Emit multiple intermediate events
for (let i = 0; i < 5; i++) {
sendEvent(intermediateEvent.with(`Progress: ${i * 20}%`));
}
return resultEvent.with("Completed");
});
// Run the workflow
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with("Start processing"));
// Process events as they arrive
for await (const event of stream) {
if (intermediateEvent.include(event)) {
console.log(event.data); // Show progress updates
} else if (resultEvent.include(event)) {
console.log("Final result:", event.data);
break; // Exit the loop when done
}
}
class ComputeResultEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
```
## Using the Stream Utilities
Workflows provide utility functions to make working with streams easier:
```ts
import { createWorkflow, workflowEvent, until, collect } from "llamaindex";
const startEvent = workflowEvent<void>();
const progressEvent = workflowEvent<number>();
const resultEvent = workflowEvent<string>();
const workflow = createWorkflow();
workflow.handle([startEvent], () => {
const { sendEvent } = getContext();
// Emit progress events
for (let i = 0; i < 100; i += 10) {
sendEvent(progressEvent.with(i));
}
return resultEvent.with("Complete");
});
// Run the workflow and collect events until a condition is met
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with());
// Collect all events until resultEvent is encountered
const events = await collect(until(stream, (event) => resultEvent.include(event)));
// Filter only progress events
const progressEvents = events.filter(event => progressEvent.include(event));
console.log(`Received ${progressEvents.length} progress updates`);
```
## Conditional Stream Processing
You can conditionally process events and even stop the stream early:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
const startEvent = workflowEvent<number>();
const dataEvent = workflowEvent<number>();
const thresholdEvent = workflowEvent<void>();
const resultEvent = workflowEvent<number[]>();
const workflow = createWorkflow();
workflow.handle([startEvent], (event) => {
const { sendEvent } = getContext();
const max = event.data;
for (let i = 0; i < max; i++) {
sendEvent(dataEvent.with(i));
if (i >= 10) {
// Signal that we've hit a threshold
sendEvent(thresholdEvent.with());
}
}
return resultEvent.with(Array.from({ length: max }, (_, i) => i));
});
// Run the workflow
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with(100)); // Generate 100 numbers
const results = [];
let hitThreshold = false;
// Process the stream
for await (const event of stream) {
if (dataEvent.include(event)) {
results.push(event.data);
} else if (thresholdEvent.include(event)) {
hitThreshold = true;
break; // Stop processing early
}
}
type ContextData = {
sum: number;
}
console.log(`Collected ${results.length} items before ${hitThreshold ? 'hitting threshold' : 'completion'}`);
```
const workflow = new Workflow<ContextData, number, number>();
workflow.addStep({
inputs: [StartEvent<number>],
outputs: [StopEvent<number>]
}, async (context, startEvent) => {
const total = startEvent.data;
for (let i = 0; i < total; i++) {
context.sendEvent(new ComputeEvent(i));
}
const computeResults = await Promise.all(Array.from({ length: total }).map(() => context.requireEvent(ComputeResultEvent)));
// Workflow API allows you to start events in parallel and wait for all of them to finish
context.data.sum = computeResults.reduce((acc, curr) => acc + curr.data, 0);
return new StopEvent(context.data.sum);
## Integration with UI Frameworks
Workflow streams can be easily integrated with UI frameworks like React to create responsive interfaces:
```tsx
// In a React component
import { useEffect, useState } from 'react';
import { createWorkflow, workflowEvent } from "llamaindex";
function StreamingComponent() {
const [updates, setUpdates] = useState([]);
const [isComplete, setIsComplete] = useState(false);
useEffect(() => {
// Set up workflow
const startEvent = workflowEvent<void>();
const updateEvent = workflowEvent<string>();
const completeEvent = workflowEvent<void>();
const workflow = createWorkflow();
workflow.handle([startEvent], () => {
const { sendEvent } = getContext();
// Simulate async updates
const intervals = [
setTimeout(() => sendEvent(updateEvent.with("First update")), 500),
setTimeout(() => sendEvent(updateEvent.with("Second update")), 1000),
setTimeout(() => sendEvent(updateEvent.with("Final update")), 1500),
setTimeout(() => sendEvent(completeEvent.with()), 2000)
];
// Cleanup function
getContext().signal.onabort = () => {
intervals.forEach(clearTimeout);
};
});
// Run the workflow
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with());
// Process events
const processEvents = async () => {
for await (const event of stream) {
if (updateEvent.include(event)) {
setUpdates(prev => [...prev, event.data]);
} else if (completeEvent.include(event)) {
setIsComplete(true);
break;
}
}
};
processEvents();
// Cleanup
return () => {
// The workflow will be aborted when the component unmounts
};
}, []);
return (
<div>
<h2>Streaming Updates</h2>
<ul>
{updates.map((update, i) => (
<li key={i}>{update}</li>
))}
</ul>
{isComplete && <div>Process complete!</div>}
</div>
);
}
```
## Server-Sent Events (SSE)
Workflows are also suitable for implementing Server-Sent Events:
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
import express from 'express';
// Define events
const startEvent = workflowEvent<void>();
const dataEvent = workflowEvent<string>();
// Create workflow
const workflow = createWorkflow();
workflow.handle([startEvent], () => {
const { sendEvent } = getContext();
// Send periodic updates
const intervals = [
setInterval(() => {
sendEvent(dataEvent.with(`Update: ${new Date().toISOString()}`));
}, 1000)
];
// Cleanup
getContext().signal.onabort = () => {
intervals.forEach(clearInterval);
};
});
// Set up Express server
const app = express();
app.get('/events', (req, res) => {
// Set headers for SSE
res.setHeader('Content-Type', 'text/event-stream');
res.setHeader('Cache-Control', 'no-cache');
res.setHeader('Connection', 'keep-alive');
// Run workflow
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with());
// Handle client disconnect
req.on('close', () => {
// This will trigger the abort signal in the workflow
});
// Process and send events
(async () => {
for await (const event of stream) {
if (dataEvent.include(event)) {
res.write(`data: ${JSON.stringify(event.data)}\n\n`);
}
}
})();
});
app.listen(3000, () => {
console.log('SSE server running on port 3000');
});
```
We define a parallel computation workflow that computes the sum of numbers from 0 to `total`.
## Advanced Techniques
The workflow sends `ComputeEvent` events for each number and waits for `ComputeResultEvent` events. After receiving all `ComputeResultEvent` events, the workflow returns the sum as a `StopEvent`.
### Flow Control
What if we want cutoff if the sum exceeds a certain value?
You can implement flow control with backpressure in your streaming workflows:
## Streaming
```ts
import { createWorkflow, workflowEvent } from "llamaindex";
```ts twoslash
import { Workflow, WorkflowEvent, StartEvent, StopEvent } from '@llamaindex/workflow';
import { StopCircle } from 'lucide-react';
class ComputeEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
}
class ComputeResultEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
}
// This example shows how to process items with controlled concurrency
const processItems = async (items, maxConcurrency = 3) => {
const startEvent = workflowEvent<string[]>();
const processItemEvent = workflowEvent<string>();
const itemProcessedEvent = workflowEvent<string>();
const resultEvent = workflowEvent<string[]>();
const workflow = createWorkflow();
// Handler to process individual items
workflow.handle([processItemEvent], async (event) => {
// Simulate processing time
await new Promise(resolve => setTimeout(resolve, 100));
return itemProcessedEvent.with(`Processed: ${event.data}`);
});
// Main workflow handler
workflow.handle([startEvent], async (event) => {
const { sendEvent, stream } = getContext();
const results = [];
// Process with controlled concurrency
const items = event.data;
let inProgress = 0;
let itemIndex = 0;
// Start initial batch of items
while (inProgress < maxConcurrency && itemIndex < items.length) {
sendEvent(processItemEvent.with(items[itemIndex++]));
inProgress++;
}
// Process items and collect results
for await (const event of stream) {
if (itemProcessedEvent.include(event)) {
results.push(event.data);
inProgress--;
// Add next item if available
if (itemIndex < items.length) {
sendEvent(processItemEvent.with(items[itemIndex++]));
inProgress++;
} else if (inProgress === 0) {
// All done
break;
}
}
}
return resultEvent.with(results);
});
// Run the workflow
const { stream, sendEvent } = workflow.createContext();
sendEvent(startEvent.with(items));
// Wait for final result
for await (const event of stream) {
if (resultEvent.include(event)) {
return event.data;
}
}
return [];
};
type ContextData = {
sum: number;
}
const workflow = new Workflow<ContextData, number, number>();
// ---cut---
const context = workflow.run(1000, {
sum: 0
});
for await (const event of context) {
if (event instanceof ComputeEvent) {
if (context.data.sum > 100) {
throw new Error('Sum exceeds 100');
}
}
if (event instanceof StopEvent) {
console.log('result', event.data);
}
}
```
You can define more custom logic using `AsyncIterable` interface.
For example. I just want to stop the workflow if I get a `ComputeResultEvent`
```ts twoslash
import { Workflow, WorkflowEvent, StartEvent, StopEvent } from '@llamaindex/workflow';
import { StopCircle } from 'lucide-react';
class ComputeEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
}
class ComputeResultEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
}
type ContextData = {
sum: number;
}
const workflow = new Workflow<ContextData, number, number>();
// ---cut---
async function compute() {
const context = workflow.run(1000, {
sum: 0
});
for await (const event of context) {
if (event instanceof ComputeResultEvent) {
return event.data;
}
}
throw new Error('UNREACHABLE');
}
const result = await compute();
```
### Streaming with UI
You can use the `Workflow` API with UI libraries like React.
```tsx twoslash
// @filename: utils.ts
export async function runWithoutBlocking(fn: () => Promise<void>) {
fn();
}
// @filename: action.ts
// ---cut---
'use server';
// "use server" is required to enable server side feature in React
import { createStreamableUI } from 'ai/rsc';
import { runWithoutBlocking } from './utils';
// ---cut-start---
import { Workflow, WorkflowEvent, StartEvent, StopEvent } from '@llamaindex/workflow';
class ComputeEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
}
class ComputeResultEvent extends WorkflowEvent<number> {
constructor(data: number) {
super(data);
}
}
type ContextData = {
sum: number;
}
const workflow = new Workflow<ContextData, number, number>();
const min = 100;
const max = 1000;
workflow.addStep(
{
inputs: [ComputeEvent],
outputs: [ComputeResultEvent]
},
async (context, event) => {
await new Promise((resolve) =>
setTimeout(resolve, Math.floor(Math.random() * (max - min + 1) + min))
);
return new ComputeResultEvent(event.data);
}
// Usage
const results = await processItems(
Array.from({ length: 20 }, (_, i) => `Item ${i}`)
);
// ---cut-end---
export async function compute() {
'use server';
const ui = createStreamableUI();
const context = workflow.run(100, {
sum: 0
});
runWithoutBlocking(async () => {
for await (const event of context) {
if (event instanceof ComputeResultEvent) {
// Update UI
} else if (event instanceof StopEvent) {
// Update UI
}
// ...
}
});
return ui.value;
}
console.log(results);
```
<WorkflowStreamingDemo />
This pattern allows you to:
1. Process large datasets without overwhelming system resources
2. Control the level of concurrency
3. Process data as it becomes available
4. Create efficient data pipelines
## Next Steps
Now that you've learned about streaming with workflows, explore more advanced topics:
- [Advanced Event Handling](./advanced-events.mdx)
- [Integration Workflows with other LlamaIndex features](./llamaindex-integration.mdx)