📄 tanstack/pacer/latest/docs/framework/react/reference/functions/useAsyncDebouncer

function useAsyncDebouncer<TFn, TSelected>(
   fn, 
   options, 
selector): ReactAsyncDebouncer<TFn, TSelected>;


function useAsyncDebouncer<TFn, TSelected>(
   fn, 
   options, 
selector): ReactAsyncDebouncer<TFn, TSelected>;

Defined in: react-pacer/src/async-debouncer/useAsyncDebouncer.ts:150

A low-level React hook that creates an AsyncDebouncer instance to delay execution of an async function.

This hook is designed to be flexible and state-management agnostic - it simply returns a debouncer instance that you can integrate with any state management solution (useState, Redux, Zustand, Jotai, etc).

Async debouncing ensures that an async function only executes after a specified delay has passed since its last invocation. Each new invocation resets the delay timer. This is useful for handling frequent events like window resizing or input changes where you only want to execute the handler after the events have stopped occurring.

Unlike throttling which allows execution at regular intervals, debouncing prevents any execution until the function stops being called for the specified delay period.

Unlike the non-async Debouncer, this async version supports returning values from the debounced function, making it ideal for API calls and other async operations where you want the result of the maybeExecute call instead of setting the result on a state variable from within the debounced function.

Error Handling:

If an onError handler is provided, it will be called with the error and debouncer instance
If throwOnError is true (default when no onError handler is provided), the error will be thrown
If throwOnError is false (default when onError handler is provided), the error will be swallowed
Both onError and throwOnError can be used together - the handler will be called before any error is thrown
The error state can be checked using the underlying AsyncDebouncer instance

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:

canLeadingExecute: Whether the debouncer can execute on the leading edge
errorCount: Number of function executions that have resulted in errors
isExecuting: Whether the debounced function is currently executing asynchronously
isPending: Whether the debouncer is waiting for the timeout to trigger execution
lastArgs: The arguments from the most recent call to maybeExecute
lastResult: The result from the most recent successful function execution
settleCount: Number of function executions that have completed (success or error)
status: Current execution status ('disabled' | 'idle' | 'pending' | 'executing' | 'settled')
successCount: Number of function executions that have completed successfully

Type Parameters
--------------- ### TFn

TFn extends AnyAsyncFunction

### TSelected

TSelected = { }

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

TFn

### options

AsyncDebouncerOptions<TFn>

### selector

(state) => TSelected

Returns
-------

ReactAsyncDebouncer <TFn, TSelected>

Example
-------

tsx

// Default behavior - no reactive state subscriptions
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  { wait: 500 }
);

// Opt-in to re-render when execution state changes (optimized for loading indicators)
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  { wait: 500 },
  (state) => ({
    isExecuting: state.isExecuting,
    isPending: state.isPending
  })
);

// Opt-in to re-render when results are available (optimized for data display)
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  { wait: 500 },
  (state) => ({
    lastResult: state.lastResult,
    successCount: state.successCount
  })
);

// Opt-in to re-render when error state changes (optimized for error handling)
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  {
    wait: 500,
    onError: (error) => console.error('Search failed:', error)
  },
  (state) => ({
    errorCount: state.errorCount,
    status: state.status
  })
);

// With state management
const [results, setResults] = useState([]);
const { maybeExecute, state } = useAsyncDebouncer(
  async (searchTerm) => {
    const data = await searchAPI(searchTerm);
    setResults(data);
  },
  {
    wait: 300,
    leading: true,   // Execute immediately on first call
    trailing: false, // Skip trailing edge updates
    onError: (error) => {
      console.error('API call failed:', error);
    }
  }
);

// Access the selected state (will be empty object {} unless selector provided)
const { isExecuting, lastResult } = state;


// Default behavior - no reactive state subscriptions
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  { wait: 500 }
);

// Opt-in to re-render when execution state changes (optimized for loading indicators)
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  { wait: 500 },
  (state) => ({
    isExecuting: state.isExecuting,
    isPending: state.isPending
  })
);

// Opt-in to re-render when results are available (optimized for data display)
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  { wait: 500 },
  (state) => ({
    lastResult: state.lastResult,
    successCount: state.successCount
  })
);

// Opt-in to re-render when error state changes (optimized for error handling)
const searchDebouncer = useAsyncDebouncer(
  async (query: string) => {
    const results = await api.search(query);
    return results;
  },
  {
    wait: 500,
    onError: (error) => console.error('Search failed:', error)
  },
  (state) => ({
    errorCount: state.errorCount,
    status: state.status
  })
);

// With state management
const [results, setResults] = useState([]);
const { maybeExecute, state } = useAsyncDebouncer(
  async (searchTerm) => {
    const data = await searchAPI(searchTerm);
    setResults(data);
  },
  {
    wait: 300,
    leading: true,   // Execute immediately on first call
    trailing: false, // Skip trailing edge updates
    onError: (error) => {
      console.error('API call failed:', error);
    }
  }
);

// Access the selected state (will be empty object {} unless selector provided)
const { isExecuting, lastResult } = state;

Edit on GitHub

useDebouncedValue

useAsyncDebouncedCallback

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