Preact Example: UseDebouncedValue

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import { useState } from 'preact/hooks'
import { render } from 'preact'
import type { JSX } from 'preact'
import { useDebouncedValue } from '@tanstack/preact-pacer/debouncer'

function App1() {
  const [instantCount, setInstantCount] = useState(0)

  function increment() {
    setInstantCount((c) => c + 1)
  }

  // highest-level hook that watches an instant local state value and returns a debounced value
  const [debouncedCount] = useDebouncedValue(instantCount, {
    wait: 500,
    // enabled: () => instantCount > 2, // optional, defaults to true
    // leading: true, // optional, defaults to false
    // Alternative to debouncer.Subscribe: pass a selector as 3rd arg to cause re-renders and subscribe to state
    // (state) => state,
  })

  return (
    <div>
      <h1>TanStack Pacer useDebouncedValue Example 1</h1>
      <table>
        <tbody>
          <tr>
            <td>Instant Count:</td>
            <td>{instantCount}</td>
          </tr>
          <tr>
            <td>Debounced Count:</td>
            <td>{debouncedCount}</td>
          </tr>
        </tbody>
      </table>
      <div>
        <button onClick={increment}>Increment</button>
      </div>
    </div>
  )
}

function App2() {
  const [instantSearch, setInstantSearch] = useState('')

  // highest-level hook that watches an instant local state value and returns a debounced value
  // optionally, grab the debouncer from the last index of the returned array
  const [debouncedSearch] = useDebouncedValue(instantSearch, {
    wait: 500,
    enabled: instantSearch.length > 2, // optional, defaults to true
    // Alternative to debouncer.Subscribe: pass a selector as 3rd arg to cause re-renders and subscribe to state
    // (state) => state,
  })

  function handleSearchChange(e: JSX.TargetedEvent<HTMLInputElement>) {
    setInstantSearch(e.currentTarget.value)
  }

  return (
    <div>
      <h1>TanStack Pacer useDebouncedValue Example 2</h1>
      <div>
        <input
          autoFocus
          type="search"
          value={instantSearch}
          onInput={handleSearchChange}
          placeholder="Type to search..."
          style={{ width: '100%' }}
        />
      </div>
      <table>
        <tbody>
          <tr>
            <td>Instant Search:</td>
            <td>{instantSearch}</td>
          </tr>
          <tr>
            <td>Debounced Search:</td>
            <td>{debouncedSearch}</td>
          </tr>
        </tbody>
      </table>
    </div>
  )
}

function App3() {
  const [currentValue, setCurrentValue] = useState(50)
  const [instantExecutionCount, setInstantExecutionCount] = useState(0)

  // highest-level hook that watches an instant local state value and returns a debounced value
  const [debouncedValue, debouncer] = useDebouncedValue(currentValue, {
    wait: 250,
    // Alternative to debouncer.Subscribe: pass a selector as 3rd arg to cause re-renders and subscribe to state
    // (state) => state,
  })

  function handleRangeChange(e: JSX.TargetedEvent<HTMLInputElement>) {
    const newValue = parseInt(e.currentTarget.value, 10)
    setCurrentValue(newValue)
    setInstantExecutionCount((c) => c + 1)
  }

  return (
    <div>
      <h1>TanStack Pacer useDebouncedValue Example 3</h1>
      <div style={{ marginBottom: '20px' }}>
        <label>
          Current Range:
          <input
            type="range"
            min="0"
            max="100"
            value={currentValue}
            onInput={handleRangeChange}
            style={{ width: '100%' }}
          />
          <span>{currentValue}</span>
        </label>
      </div>
      <div style={{ marginBottom: '20px' }}>
        <label>
          Debounced Range (Readonly):
          <input
            type="range"
            min="0"
            max="100"
            value={debouncedValue}
            readOnly
            style={{ width: '100%' }}
          />
          <span>{debouncedValue}</span>
        </label>
      </div>
      <debouncer.Subscribe
        selector={(state) => ({
          isPending: state.isPending,
          executionCount: state.executionCount,
        })}
      >
        {({ isPending, executionCount }) => (
          <>
            <table>
              <tbody>
                <tr>
                  <td>Is Pending:</td>
                  <td>{isPending.toString()}</td>
                </tr>
                <tr>
                  <td>Instant Executions:</td>
                  <td>{instantExecutionCount}</td>
                </tr>
                <tr>
                  <td>Debounced Executions:</td>
                  <td>{executionCount}</td>
                </tr>
                <tr>
                  <td>Saved Executions:</td>
                  <td>{instantExecutionCount - executionCount}</td>
                </tr>
                <tr>
                  <td>% Reduction:</td>
                  <td>
                    {instantExecutionCount === 0
                      ? '0'
                      : Math.round(
                          ((instantExecutionCount - executionCount) /
                            instantExecutionCount) *
                            100,
                        )}
                    %
                  </td>
                </tr>
              </tbody>
            </table>
            <div style={{ color: '#666', fontSize: '0.9em' }}>
              <p>Debounced to 250ms wait time</p>
            </div>
          </>
        )}
      </debouncer.Subscribe>
      <debouncer.Subscribe selector={(state) => state}>
        {(state) => (
          <pre style={{ marginTop: '20px' }}>
            {JSON.stringify(state, null, 2)}
          </pre>
        )}
      </debouncer.Subscribe>
    </div>
  )
}

const root = document.getElementById('root')!
render(
  <div>
    <App1 />
    <hr />
    <App2 />
    <hr />
    <App3 />
  </div>,
  root,
)