📄 tanstack/pacer/latest/docs/framework/solid/reference/functions/createBatcher

function createBatcher<TValue, TSelected>(
   fn, 
   initialOptions, 
selector): SolidBatcher<TValue, TSelected>;


function createBatcher<TValue, TSelected>(
   fn, 
   initialOptions, 
selector): SolidBatcher<TValue, TSelected>;

Defined in: batcher/createBatcher.ts:100

Creates a Solid-compatible Batcher instance for managing batches of items, exposing Solid signals for all stateful properties.

Features:

Batch processing of items using the provided fn function
Configurable batch size and wait time
Custom batch processing logic via getShouldExecute
Event callbacks for monitoring batch operations
All stateful properties (items, counts, etc.) are exposed as Solid signals for reactivity

The batcher collects items and processes them in batches based on:

Maximum batch size
Time-based batching (process after X milliseconds)
Custom batch processing logic via getShouldExecute

State Management and Selector
-----------------------------

The hook uses TanStack Store for reactive state management. The selector parameter allows you to specify which state changes will trigger a re-render, optimizing performance by preventing unnecessary re-renders when irrelevant state changes occur.

By default, there will be no reactive state subscriptions and you must opt-in to state tracking by providing a selector function. This prevents unnecessary re-renders and gives you full control over when your component updates. Only when you provide a selector will the component re-render when the selected state values change.

Available state properties:

executionCount: Number of batch executions that have been completed
isRunning: Whether the batcher is currently running (not stopped)
items: Array of items currently queued for batching
totalItemsProcessed: Total number of individual items that have been processed across all batches

Example usage:

tsx

// Default behavior - no reactive state subscriptions
const batcher = createBatcher(
  (items) => {
    // Process batch of items
    console.log('Processing batch:', items);
  },
  {
    maxSize: 5,
    wait: 2000,
    onExecute: (batcher) => console.log('Batch executed'),
    getShouldExecute: (items) => items.length >= 3
  }
);

// Opt-in to re-render when items or isRunning changes (optimized for UI updates)
const batcher = createBatcher(
  (items) => console.log('Processing batch:', items),
  { maxSize: 5, wait: 2000 },
  (state) => ({ items: state.items, isRunning: state.isRunning })
);

// Opt-in to re-render when execution metrics change (optimized for tracking progress)
const batcher = createBatcher(
  (items) => console.log('Processing batch:', items),
  { maxSize: 5, wait: 2000 },
  (state) => ({
    executionCount: state.executionCount,
    totalItemsProcessed: state.totalItemsProcessed
  })
);

// Add items to batch
batcher.addItem('task1');
batcher.addItem('task2');

// Control the batcher
batcher.stop();  // Pause processing
batcher.start(); // Resume processing

// Access the selected state (will be empty object {} unless selector provided)
const { items, isRunning } = batcher.state();


// Default behavior - no reactive state subscriptions
const batcher = createBatcher(
  (items) => {
    // Process batch of items
    console.log('Processing batch:', items);
  },
  {
    maxSize: 5,
    wait: 2000,
    onExecute: (batcher) => console.log('Batch executed'),
    getShouldExecute: (items) => items.length >= 3
  }
);

// Opt-in to re-render when items or isRunning changes (optimized for UI updates)
const batcher = createBatcher(
  (items) => console.log('Processing batch:', items),
  { maxSize: 5, wait: 2000 },
  (state) => ({ items: state.items, isRunning: state.isRunning })
);

// Opt-in to re-render when execution metrics change (optimized for tracking progress)
const batcher = createBatcher(
  (items) => console.log('Processing batch:', items),
  { maxSize: 5, wait: 2000 },
  (state) => ({
    executionCount: state.executionCount,
    totalItemsProcessed: state.totalItemsProcessed
  })
);

// Add items to batch
batcher.addItem('task1');
batcher.addItem('task2');

// Control the batcher
batcher.stop();  // Pause processing
batcher.start(); // Resume processing

// Access the selected state (will be empty object {} unless selector provided)
const { items, isRunning } = batcher.state();

Type Parameters
--------------- ### TValue

TValue

### TSelected

TSelected = { }

Parameters
---------- ### fn

(items) => void

### initialOptions

BatcherOptions<TValue> = {}

### selector

(state) => TSelected

Returns
-------

SolidBatcher <TValue, TSelected>