React Example: UseAsyncRateLimiterWithPersister

Github StackBlitz CodeSandbox

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 [windowType, setWindowType] = useState<'fixed' | 'sliding'>('fixed')
  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)
  }

  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: windowType,
      limit: 3, // Maximum 2 requests
      window: 3000, // per 1 second
      onReject: (_args, 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(),
    },
    // Alternative to setSearchAsyncRateLimiter.Subscribe: pass a selector as 3rd arg to cause re-renders and subscribe to state
    // (state) => state,
  )

  useEffect(() => {
    rateLimiterPersister.saveState(setSearchAsyncRateLimiter.store.state)
  }, [setSearchAsyncRateLimiter.store.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 (with persister)</h1>
      <div style={{ display: 'grid', gap: '0.5rem', marginBottom: '1rem' }}>
        <label>
          <input
            type="radio"
            name="windowType"
            value="fixed"
            checked={windowType === 'fixed'}
            onChange={() => setWindowType('fixed')}
          />
          Fixed Window
        </label>
        <label>
          <input
            type="radio"
            name="windowType"
            value="sliding"
            checked={windowType === 'sliding'}
            onChange={() => setWindowType('sliding')}
          />
          Sliding Window
        </label>
      </div>
      <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>}
      <setSearchAsyncRateLimiter.Subscribe
        selector={(state) => ({
          successCount: state.successCount,
          rejectionCount: state.rejectionCount,
          isExecuting: state.isExecuting,
        })}
      >
        {({ successCount, rejectionCount, isExecuting }) => (
          <div>
            <table>
              <tbody>
                <tr>
                  <td>API calls made:</td>
                  <td>{successCount}</td>
                </tr>
                <tr>
                  <td>Rejected calls:</td>
                  <td>{rejectionCount}</td>
                </tr>
                <tr>
                  <td>Is executing:</td>
                  <td>{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>
        )}
      </setSearchAsyncRateLimiter.Subscribe>
      <setSearchAsyncRateLimiter.Subscribe selector={(state) => state}>
        {(state) => (
          <pre style={{ marginTop: '20px' }}>
            {JSON.stringify(state, null, 2)}
          </pre>
        )}
      </setSearchAsyncRateLimiter.Subscribe>
    </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 [windowType, setWindowType] = useState<'fixed' | 'sliding'>('fixed')
  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)
  }

  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: windowType,
      limit: 3, // Maximum 2 requests
      window: 3000, // per 1 second
      onReject: (_args, 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(),
    },
    // Alternative to setSearchAsyncRateLimiter.Subscribe: pass a selector as 3rd arg to cause re-renders and subscribe to state
    // (state) => state,
  )

  useEffect(() => {
    rateLimiterPersister.saveState(setSearchAsyncRateLimiter.store.state)
  }, [setSearchAsyncRateLimiter.store.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 (with persister)</h1>
      <div style={{ display: 'grid', gap: '0.5rem', marginBottom: '1rem' }}>
        <label>
          <input
            type="radio"
            name="windowType"
            value="fixed"
            checked={windowType === 'fixed'}
            onChange={() => setWindowType('fixed')}
          />
          Fixed Window
        </label>
        <label>
          <input
            type="radio"
            name="windowType"
            value="sliding"
            checked={windowType === 'sliding'}
            onChange={() => setWindowType('sliding')}
          />
          Sliding Window
        </label>
      </div>
      <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>}
      <setSearchAsyncRateLimiter.Subscribe
        selector={(state) => ({
          successCount: state.successCount,
          rejectionCount: state.rejectionCount,
          isExecuting: state.isExecuting,
        })}
      >
        {({ successCount, rejectionCount, isExecuting }) => (
          <div>
            <table>
              <tbody>
                <tr>
                  <td>API calls made:</td>
                  <td>{successCount}</td>
                </tr>
                <tr>
                  <td>Rejected calls:</td>
                  <td>{rejectionCount}</td>
                </tr>
                <tr>
                  <td>Is executing:</td>
                  <td>{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>
        )}
      </setSearchAsyncRateLimiter.Subscribe>
      <setSearchAsyncRateLimiter.Subscribe selector={(state) => state}>
        {(state) => (
          <pre style={{ marginTop: '20px' }}>
            {JSON.stringify(state, null, 2)}
          </pre>
        )}
      </setSearchAsyncRateLimiter.Subscribe>
    </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)
  }
})