useThrottler

function useThrottler<TFn, TSelected>(
   fn,
   options,
selector?): ReactThrottler<TFn, TSelected>;

Defined in: throttler/useThrottler.ts:168

A low-level React hook that creates a Throttler instance that limits how often the provided function can execute.

This hook is designed to be flexible and state-management agnostic - it simply returns a throttler instance that you can integrate with any state management solution (useState, Redux, Zustand, Jotai, etc). For a simpler and higher-level hook that integrates directly with React's useState, see useThrottledState.

Throttling ensures a function executes at most once within a specified time window, regardless of how many times it is called. This is useful for rate-limiting expensive operations or UI updates.

State Management and Selector

The hook uses TanStack Store for reactive state management. You can subscribe to state changes in two ways:

1. Using throttler.Subscribe HOC (Recommended for component tree subscriptions)

Use the Subscribe HOC to subscribe to state changes deep in your component tree without needing to pass a selector to the hook. This is ideal when you want to subscribe to state in child components.

2. Using the selector parameter (For hook-level subscriptions)

The selector parameter allows you to specify which state changes will trigger a re-render at the hook level, 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 or using the Subscribe HOC. This prevents unnecessary re-renders and gives you full control over when your component updates.

Available state properties:

• executionCount: Number of function executions that have been completed
• lastArgs: The arguments from the most recent call to maybeExecute
• lastExecutionTime: Timestamp of the last function execution in milliseconds
• nextExecutionTime: Timestamp when the next execution can occur in milliseconds
• isPending: Whether the throttler is waiting for the timeout to trigger execution
• status: Current execution status ('disabled' | 'idle' | 'pending')

Unmount behavior

By default, the hook cancels any pending execution when the component unmounts. Use the onUnmount option to customize this. For example, to flush pending work instead:

const throttler = useThrottler(fn, {
  wait: 1000,
  onUnmount: (t) => t.flush()
});

Type Parameters

TFn

TFn extends AnyFunction

TSelected

TSelected = { }

Parameters

fn

TFn

options

ReactThrottlerOptions<TFn, TSelected>

selector?

(state) => TSelected

Returns

ReactThrottler<TFn, TSelected>

Example

// Default behavior - no reactive state subscriptions
const [value, setValue] = useState(0);
const throttler = useThrottler(setValue, { wait: 1000 });

// Subscribe to state changes deep in component tree using Subscribe HOC
<throttler.Subscribe selector={(state) => ({ isPending: state.isPending })}>
  {({ isPending }) => (
    <div>{isPending ? 'Throttling...' : 'Ready'}</div>
  )}
</throttler.Subscribe>

// Opt-in to re-render when execution count changes at hook level (optimized for tracking executions)
const [value, setValue] = useState(0);
const throttler = useThrottler(
  setValue,
  { wait: 1000 },
  (state) => ({ executionCount: state.executionCount })
);

// Opt-in to re-render when throttling state changes (optimized for loading indicators)
const [value, setValue] = useState(0);
const throttler = useThrottler(
  setValue,
  { wait: 1000 },
  (state) => ({
    isPending: state.isPending,
    status: state.status
  })
);

// Opt-in to re-render when timing information changes (optimized for timing displays)
const [value, setValue] = useState(0);
const throttler = useThrottler(
  setValue,
  { wait: 1000 },
  (state) => ({
    lastExecutionTime: state.lastExecutionTime,
    nextExecutionTime: state.nextExecutionTime
  })
);

// With any state manager
const throttler = useThrottler(
  (value) => stateManager.setState(value),
  {
    wait: 2000,
    leading: true,   // Execute immediately on first call
    trailing: false  // Skip trailing edge updates
  }
);

// Access the selected state (will be empty object {} unless selector provided)
const { executionCount, isPending } = throttler.state;