createAsyncThrottler

function createAsyncThrottler<TFn, TSelected>(
   scope,
   fn,
   options,
selector?): AlpineAsyncThrottler<TFn, TSelected>;

Defined in: async-throttler/createAsyncThrottler.ts:95

Creates and retains the AsyncThrottler for its Alpine owner.

Limits execution to at most one call per wait interval. Leading and trailing options control immediate and deferred execution; the trailing call uses the latest arguments.

The callback may return a Promise. Core result, error, retry, and abort behavior is preserved. Use onSuccess, onError, and onSettled for execution outcomes.

State and subscriptions

Pass a selector to track only the state consumed by the owner. The default selection is {}, so utility state changes do not update the owner unless it opts in. Selection uses shallow comparison. The raw store remains available for additional subscriptions. Use utility.subscribe(childScope, selector) for a child subscription. It returns a getter and cleans up with the child without canceling the parent utility.

Available state fields:

• errorCount: Number of function executions that have resulted in errors
• isExecuting: Whether the throttled function is currently executing asynchronously
• isPending: Whether the throttler is waiting for the timeout to trigger execution
• lastArgs: The arguments from the most recent call to maybeExecute
• lastExecutionTime: Timestamp of the last function execution in milliseconds
• lastResult: The result from the most recent successful function execution
• maybeExecuteCount: Number of times maybeExecute has been called (for reduction calculations)
• nextExecutionTime: Timestamp when the next execution can occur in milliseconds
• settleCount: Number of function executions that have completed (either successfully or with errors)
• status: Current execution status - 'idle' when not active, 'pending' when waiting, 'executing' when running, 'settled' when completed
• successCount: Number of function executions that have completed successfully

Options and ownership

Pass an options object with property getters or a factory. Top-level properties are read reactively; function-valued core options remain callbacks. Local options override provider defaults. Updates retain the utility, its store, counters, and pending work. Destroying the owning scope calls cancel() and abort(). onUnmount replaces default cleanup and receives the same adapter instance. A custom callback must perform all required cleanup. Use flush() where supported to finish pending work.

Type Parameters

TFn

TFn extends AnyAsyncFunction

TSelected

TSelected = { }

Parameters

scope

PacerScope

Owner of option updates, subscriptions, and cleanup.

fn

TFn

Function executed by the utility.

options

AlpinePacerOptions<AlpineAsyncThrottlerOptions<TFn, TSelected>>

Core options or a reactive factory, plus an optional onUnmount callback.

selector?

(state) => TSelected

Selects state that updates the owner. Omit to leave selected state empty.

Returns

AlpineAsyncThrottler<TFn, TSelected>

The retained utility instance with selected state and child subscriptions.

Example

import { createAsyncThrottler } from '@tanstack/alpine-pacer'

const utility = createAsyncThrottler(
  scope, async (value: string) => { console.log(value) },
  { wait: 500 },
  (state) => ({ isPending: state.isPending }),
)
utility.maybeExecute('item')
// Selected state: utility.state.isPending