React Example: UseAsyncRateLimiter

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import { useEffect, useState } from 'react'
import ReactDOM from 'react-dom/client'
import { useAsyncRateLimiter } from '@tanstack/react-pacer/async-rate-limiter'
import { useStoragePersister } from '@tanstack/react-persister/storage-persister'
import type { AsyncRateLimiterState } from '@tanstack/react-pacer/async-rate-limiter'

interface SearchResult {
  id: number
  title: string
}

// Simulate API call with fake data
const fakeApi = async (term: string): Promise<Array<SearchResult>> => {
  await new Promise((resolve) => setTimeout(resolve, 300)) // Simulate network delay
  return [
    { id: 1, title: `${term} result ${Math.floor(Math.random() * 100)}` },
    { id: 2, title: `${term} result ${Math.floor(Math.random() * 100)}` },
    { id: 3, title: `${term} result ${Math.floor(Math.random() * 100)}` },
  ]
}

function App() {
  const [searchTerm, setSearchTerm] = useState('')
  const [results, setResults] = useState<Array<SearchResult>>([])
  const [error, setError] = useState<Error | null>(null)

  // The function that will become rate limited
  const handleSearch = async (term: string) => {
    if (!term) {
      setResults([])
      return
    }

    // throw new Error('Test error') // you don't have to catch errors here (though you still can). The onError optional handler will catch it

    const data = await fakeApi(term)
    setResults(data)
    setError(null)

    console.log(setSearchAsyncRateLimiter.state.successCount)
  }

  const rateLimiterPersister = useStoragePersister<
    AsyncRateLimiterState<typeof handleSearch>
  >({
    key: 'my-async-rate-limiter',
    storage: localStorage,
    maxAge: 1000 * 60, // 1 minute
    buster: 'v1',
  })

  // hook that gives you an async rate limiter instance
  const setSearchAsyncRateLimiter = useAsyncRateLimiter(handleSearch, {
    // windowType: 'sliding', // default is 'fixed'
    limit: 3, // Maximum 2 requests
    window: 3000, // per 1 second
    onReject: (rateLimiter) => {
      console.log(
        `Rate limit reached. Try again in ${rateLimiter.getMsUntilNextWindow()}ms`,
      )
    },
    onError: (error) => {
      // optional error handler
      console.error('Search failed:', error)
      setError(error as Error)
      setResults([])
    },
    // optionally, you can persist the rate limiter state to localStorage
    initialState: rateLimiterPersister.loadState(),
  })

  useEffect(() => {
    rateLimiterPersister.saveState(setSearchAsyncRateLimiter.state)
  }, [setSearchAsyncRateLimiter.state])

  // get and name our rate limited function
  const handleSearchRateLimited = setSearchAsyncRateLimiter.maybeExecute

  useEffect(() => {
    console.log('mount')
    return () => {
      console.log('unmount')
      setSearchAsyncRateLimiter.reset() // cancel any pending async calls when the component unmounts
    }
  }, [])

  // instant event handler that calls both the instant local state setter and the rate limited function
  async function onSearchChange(e: React.ChangeEvent<HTMLInputElement>) {
    const newTerm = e.target.value
    setSearchTerm(newTerm)
    await handleSearchRateLimited(newTerm) // optionally await if you need to
  }

  return (
    <div>
      <h1>TanStack Pacer useAsyncRateLimiter Example</h1>
      <div>
        <input
          autoFocus
          type="search"
          value={searchTerm}
          onChange={onSearchChange}
          placeholder="Type to search..."
          style={{ width: '100%' }}
          autoComplete="new-password"
        />
      </div>
      {error && <div>Error: {error.message}</div>}
      <div>
        <table>
          <tbody>
            <tr>
              <td>API calls made:</td>
              <td>{setSearchAsyncRateLimiter.state.successCount}</td>
            </tr>
            <tr>
              <td>Rejected calls:</td>
              <td>{setSearchAsyncRateLimiter.state.rejectionCount}</td>
            </tr>
            <tr>
              <td>Is executing:</td>
              <td>
                {setSearchAsyncRateLimiter.state.isExecuting ? 'Yes' : 'No'}
              </td>
            </tr>
            <tr>
              <td>Results:</td>
              <td>
                {results.length > 0 ? (
                  <ul>
                    {results.map((item) => (
                      <li key={item.id}>{item.title}</li>
                    ))}
                  </ul>
                ) : (
                  'No results'
                )}
              </td>
            </tr>
          </tbody>
        </table>
      </div>
      <pre style={{ marginTop: '20px' }}>
        {JSON.stringify(setSearchAsyncRateLimiter.state, null, 2)}
      </pre>
    </div>
  )
}

const root = ReactDOM.createRoot(document.getElementById('root')!)

let mounted = true
root.render(<App />)

// demo unmounting and cancellation
document.addEventListener('keydown', (e) => {
  if (e.key === 'Enter') {
    mounted = !mounted
    root.render(mounted ? <App /> : null)
  }
})

import { useEffect, useState } from 'react'
import ReactDOM from 'react-dom/client'
import { useAsyncRateLimiter } from '@tanstack/react-pacer/async-rate-limiter'
import { useStoragePersister } from '@tanstack/react-persister/storage-persister'
import type { AsyncRateLimiterState } from '@tanstack/react-pacer/async-rate-limiter'

interface SearchResult {
  id: number
  title: string
}

// Simulate API call with fake data
const fakeApi = async (term: string): Promise<Array<SearchResult>> => {
  await new Promise((resolve) => setTimeout(resolve, 300)) // Simulate network delay
  return [
    { id: 1, title: `${term} result ${Math.floor(Math.random() * 100)}` },
    { id: 2, title: `${term} result ${Math.floor(Math.random() * 100)}` },
    { id: 3, title: `${term} result ${Math.floor(Math.random() * 100)}` },
  ]
}

function App() {
  const [searchTerm, setSearchTerm] = useState('')
  const [results, setResults] = useState<Array<SearchResult>>([])
  const [error, setError] = useState<Error | null>(null)

  // The function that will become rate limited
  const handleSearch = async (term: string) => {
    if (!term) {
      setResults([])
      return
    }

    // throw new Error('Test error') // you don't have to catch errors here (though you still can). The onError optional handler will catch it

    const data = await fakeApi(term)
    setResults(data)
    setError(null)

    console.log(setSearchAsyncRateLimiter.state.successCount)
  }

  const rateLimiterPersister = useStoragePersister<
    AsyncRateLimiterState<typeof handleSearch>
  >({
    key: 'my-async-rate-limiter',
    storage: localStorage,
    maxAge: 1000 * 60, // 1 minute
    buster: 'v1',
  })

  // hook that gives you an async rate limiter instance
  const setSearchAsyncRateLimiter = useAsyncRateLimiter(handleSearch, {
    // windowType: 'sliding', // default is 'fixed'
    limit: 3, // Maximum 2 requests
    window: 3000, // per 1 second
    onReject: (rateLimiter) => {
      console.log(
        `Rate limit reached. Try again in ${rateLimiter.getMsUntilNextWindow()}ms`,
      )
    },
    onError: (error) => {
      // optional error handler
      console.error('Search failed:', error)
      setError(error as Error)
      setResults([])
    },
    // optionally, you can persist the rate limiter state to localStorage
    initialState: rateLimiterPersister.loadState(),
  })

  useEffect(() => {
    rateLimiterPersister.saveState(setSearchAsyncRateLimiter.state)
  }, [setSearchAsyncRateLimiter.state])

  // get and name our rate limited function
  const handleSearchRateLimited = setSearchAsyncRateLimiter.maybeExecute

  useEffect(() => {
    console.log('mount')
    return () => {
      console.log('unmount')
      setSearchAsyncRateLimiter.reset() // cancel any pending async calls when the component unmounts
    }
  }, [])

  // instant event handler that calls both the instant local state setter and the rate limited function
  async function onSearchChange(e: React.ChangeEvent<HTMLInputElement>) {
    const newTerm = e.target.value
    setSearchTerm(newTerm)
    await handleSearchRateLimited(newTerm) // optionally await if you need to
  }

  return (
    <div>
      <h1>TanStack Pacer useAsyncRateLimiter Example</h1>
      <div>
        <input
          autoFocus
          type="search"
          value={searchTerm}
          onChange={onSearchChange}
          placeholder="Type to search..."
          style={{ width: '100%' }}
          autoComplete="new-password"
        />
      </div>
      {error && <div>Error: {error.message}</div>}
      <div>
        <table>
          <tbody>
            <tr>
              <td>API calls made:</td>
              <td>{setSearchAsyncRateLimiter.state.successCount}</td>
            </tr>
            <tr>
              <td>Rejected calls:</td>
              <td>{setSearchAsyncRateLimiter.state.rejectionCount}</td>
            </tr>
            <tr>
              <td>Is executing:</td>
              <td>
                {setSearchAsyncRateLimiter.state.isExecuting ? 'Yes' : 'No'}
              </td>
            </tr>
            <tr>
              <td>Results:</td>
              <td>
                {results.length > 0 ? (
                  <ul>
                    {results.map((item) => (
                      <li key={item.id}>{item.title}</li>
                    ))}
                  </ul>
                ) : (
                  'No results'
                )}
              </td>
            </tr>
          </tbody>
        </table>
      </div>
      <pre style={{ marginTop: '20px' }}>
        {JSON.stringify(setSearchAsyncRateLimiter.state, null, 2)}
      </pre>
    </div>
  )
}

const root = ReactDOM.createRoot(document.getElementById('root')!)

let mounted = true
root.render(<App />)

// demo unmounting and cancellation
document.addEventListener('keydown', (e) => {
  if (e.key === 'Enter') {
    mounted = !mounted
    root.render(mounted ? <App /> : null)
  }
})