React Example: Playground

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import React from 'react'
import ReactDOM from 'react-dom/client'

import {
  QueryClient,
  QueryClientProvider,
  useQuery,
  useQueryClient,
  useMutation,
} from '@tanstack/react-query'

import { ReactQueryDevtools } from '@tanstack/react-query-devtools'

import './styles.css'

let id = 0
let list = [
  'apple',
  'banana',
  'pineapple',
  'grapefruit',
  'dragonfruit',
  'grapes',
].map((d) => ({ id: id++, name: d, notes: 'These are some notes' }))

let errorRate = 0.05
let queryTimeMin = 1000
let queryTimeMax = 2000

const queryClient = new QueryClient()

function Root() {
  const [staleTime, setStaleTime] = React.useState(1000)
  const [cacheTime, setCacheTime] = React.useState(3000)
  const [localErrorRate, setErrorRate] = React.useState(errorRate)
  const [localFetchTimeMin, setLocalFetchTimeMin] = React.useState(queryTimeMin)
  const [localFetchTimeMax, setLocalFetchTimeMax] = React.useState(queryTimeMax)

  React.useEffect(() => {
    errorRate = localErrorRate
    queryTimeMin = localFetchTimeMin
    queryTimeMax = localFetchTimeMax
  }, [localErrorRate, localFetchTimeMax, localFetchTimeMin])

  React.useEffect(() => {
    queryClient.setDefaultOptions({
      queries: {
        staleTime,
        cacheTime,
      },
    })
  }, [cacheTime, staleTime])

  return (
    <QueryClientProvider client={queryClient}>
      <p>
        The "staleTime" and "cacheTime" durations have been altered in this
        example to show how query stale-ness and query caching work on a
        granular level
      </p>
      <div>
        Stale Time:{' '}
        <input
          type="number"
          min="0"
          step="1000"
          value={staleTime}
          onChange={(e) => setStaleTime(parseFloat(e.target.value, 10))}
          style={{ width: '100px' }}
        />
      </div>
      <div>
        Cache Time:{' '}
        <input
          type="number"
          min="0"
          step="1000"
          value={cacheTime}
          onChange={(e) => setCacheTime(parseFloat(e.target.value, 10))}
          style={{ width: '100px' }}
        />
      </div>
      <br />
      <div>
        Error Rate:{' '}
        <input
          type="number"
          min="0"
          max="1"
          step=".05"
          value={localErrorRate}
          onChange={(e) => setErrorRate(parseFloat(e.target.value, 10))}
          style={{ width: '100px' }}
        />
      </div>
      <div>
        Fetch Time Min:{' '}
        <input
          type="number"
          min="1"
          step="500"
          value={localFetchTimeMin}
          onChange={(e) => setLocalFetchTimeMin(parseFloat(e.target.value, 10))}
          style={{ width: '60px' }}
        />{' '}
      </div>
      <div>
        Fetch Time Max:{' '}
        <input
          type="number"
          min="1"
          step="500"
          value={localFetchTimeMax}
          onChange={(e) => setLocalFetchTimeMax(parseFloat(e.target.value, 10))}
          style={{ width: '60px' }}
        />
      </div>
      <br />
      <App />
      <br />
      <ReactQueryDevtools initialIsOpen />
    </QueryClientProvider>
  )
}

function App() {
  const queryClient = useQueryClient()
  const [editingIndex, setEditingIndex] = React.useState(null)
  const [views, setViews] = React.useState(['', 'fruit', 'grape'])
  // const [views, setViews] = React.useState([""]);

  return (
    <div className="App">
      <div>
        <button onClick={() => queryClient.invalidateQueries()}>
          Force Refetch All
        </button>
      </div>
      <br />
      <hr />
      {views.map((view, index) => (
        <div key={index}>
          <Todos
            initialFilter={view}
            setEditingIndex={setEditingIndex}
            onRemove={() => {
              setViews((old) => [...old, ''])
            }}
          />
          <br />
        </div>
      ))}
      <button
        onClick={() => {
          setViews((old) => [...old, ''])
        }}
      >
        Add Filter List
      </button>
      <hr />
      {editingIndex !== null ? (
        <>
          <EditTodo
            editingIndex={editingIndex}
            setEditingIndex={setEditingIndex}
          />
          <hr />
        </>
      ) : null}
      <AddTodo />
    </div>
  )
}

function Todos({ initialFilter = '', setEditingIndex }) {
  const [filter, setFilter] = React.useState(initialFilter)

  const { status, data, isFetching, error, failureCount, refetch } = useQuery({
    queryKey: ['todos', { filter }],
    queryFn: fetchTodos,
  })

  return (
    <div>
      <div>
        <label>
          Filter:{' '}
          <input value={filter} onChange={(e) => setFilter(e.target.value)} />
        </label>
      </div>
      {status === 'loading' ? (
        <span>Loading... (Attempt: {failureCount + 1})</span>
      ) : status === 'error' ? (
        <span>
          Error: {error.message}
          <br />
          <button onClick={() => refetch()}>Retry</button>
        </span>
      ) : (
        <>
          <ul>
            {data
              ? data.map((todo) => (
                  <li key={todo.id}>
                    {todo.name}{' '}
                    <button onClick={() => setEditingIndex(todo.id)}>
                      Edit
                    </button>
                  </li>
                ))
              : null}
          </ul>
          <div>
            {isFetching ? (
              <span>
                Background Refreshing... (Attempt: {failureCount + 1})
              </span>
            ) : (
              <span>&nbsp;</span>
            )}
          </div>
        </>
      )}
    </div>
  )
}

function EditTodo({ editingIndex, setEditingIndex }) {
  const queryClient = useQueryClient()

  // Don't attempt to query until editingIndex is truthy
  const { status, data, isFetching, error, failureCount, refetch } = useQuery({
    queryKey: ['todo', { id: editingIndex }],
    queryFn: () => fetchTodoById({ id: editingIndex }),
    enabled: editingIndex !== null,
  })

  const [todo, setTodo] = React.useState(data || {})

  React.useEffect(() => {
    if (editingIndex !== null && data) {
      setTodo(data)
    } else {
      setTodo({})
    }
  }, [data, editingIndex])

  const saveMutation = useMutation({
    mutationFn: patchTodo,
    onSuccess: (data) => {
      // Update `todos` and the individual todo queries when this mutation succeeds
      queryClient.invalidateQueries({ queryKey: ['todos'] })
      queryClient.setQueryData(['todo', { id: editingIndex }], data)
    },
  })

  const onSave = () => {
    saveMutation.mutate(todo)
  }

  const disableEditSave =
    status === 'loading' || saveMutation.status === 'loading'

  return (
    <div>
      <div>
        {data ? (
          <>
            <button onClick={() => setEditingIndex(null)}>Back</button> Editing
            Todo "{data.name}" (#
            {editingIndex})
          </>
        ) : null}
      </div>
      {status === 'loading' ? (
        <span>Loading... (Attempt: {failureCount + 1})</span>
      ) : error ? (
        <span>
          Error! <button onClick={() => refetch()}>Retry</button>
        </span>
      ) : (
        <>
          <label>
            Name:{' '}
            <input
              value={todo.name}
              onChange={(e) =>
                e.persist() ||
                setTodo((old) => ({ ...old, name: e.target.value }))
              }
              disabled={disableEditSave}
            />
          </label>
          <label>
            Notes:{' '}
            <input
              value={todo.notes}
              onChange={(e) =>
                e.persist() ||
                setTodo((old) => ({ ...old, notes: e.target.value }))
              }
              disabled={disableEditSave}
            />
          </label>
          <div>
            <button onClick={onSave} disabled={disableEditSave}>
              Save
            </button>
          </div>
          <div>
            {saveMutation.status === 'loading'
              ? 'Saving...'
              : saveMutation.status === 'error'
              ? saveMutation.error.message
              : 'Saved!'}
          </div>
          <div>
            {isFetching ? (
              <span>
                Background Refreshing... (Attempt: {failureCount + 1})
              </span>
            ) : (
              <span>&nbsp;</span>
            )}
          </div>
        </>
      )}
    </div>
  )
}

function AddTodo() {
  const queryClient = useQueryClient()
  const [name, setName] = React.useState('')

  const addMutation = useMutation({
    mutationFn: postTodo,
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['todos'] })
    },
  })

  return (
    <div>
      <input
        value={name}
        onChange={(e) => setName(e.target.value)}
        disabled={addMutation.status === 'loading'}
      />
      <button
        onClick={() => {
          addMutation.mutate({ name })
        }}
        disabled={addMutation.status === 'loading' || !name}
      >
        Add Todo
      </button>
      <div>
        {addMutation.status === 'loading'
          ? 'Saving...'
          : addMutation.status === 'error'
          ? addMutation.error.message
          : 'Saved!'}
      </div>
    </div>
  )
}

function fetchTodos({ signal, queryKey: [, { filter }] }) {
  console.info('fetchTodos', { filter })

  if (signal) {
    signal.addEventListener('abort', () => {
      console.info('cancelled', filter)
    })
  }

  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(
          new Error(JSON.stringify({ fetchTodos: { filter } }, null, 2)),
        )
      }
      resolve(list.filter((d) => d.name.includes(filter)))
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

function fetchTodoById({ id }) {
  console.info('fetchTodoById', { id })
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(
          new Error(JSON.stringify({ fetchTodoById: { id } }, null, 2)),
        )
      }
      resolve(list.find((d) => d.id === id))
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

function postTodo({ name, notes }) {
  console.info('postTodo', { name, notes })
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(
          new Error(JSON.stringify({ postTodo: { name, notes } }, null, 2)),
        )
      }
      const todo = { name, notes, id: id++ }
      list = [...list, todo]
      resolve(todo)
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

function patchTodo(todo) {
  console.info('patchTodo', todo)
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(new Error(JSON.stringify({ patchTodo: todo }, null, 2)))
      }
      list = list.map((d) => {
        if (d.id === todo.id) {
          return todo
        }
        return d
      })
      resolve(todo)
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

const rootElement = document.getElementById('root')
ReactDOM.createRoot(rootElement).render(<Root />)

import React from 'react'
import ReactDOM from 'react-dom/client'

import {
  QueryClient,
  QueryClientProvider,
  useQuery,
  useQueryClient,
  useMutation,
} from '@tanstack/react-query'

import { ReactQueryDevtools } from '@tanstack/react-query-devtools'

import './styles.css'

let id = 0
let list = [
  'apple',
  'banana',
  'pineapple',
  'grapefruit',
  'dragonfruit',
  'grapes',
].map((d) => ({ id: id++, name: d, notes: 'These are some notes' }))

let errorRate = 0.05
let queryTimeMin = 1000
let queryTimeMax = 2000

const queryClient = new QueryClient()

function Root() {
  const [staleTime, setStaleTime] = React.useState(1000)
  const [cacheTime, setCacheTime] = React.useState(3000)
  const [localErrorRate, setErrorRate] = React.useState(errorRate)
  const [localFetchTimeMin, setLocalFetchTimeMin] = React.useState(queryTimeMin)
  const [localFetchTimeMax, setLocalFetchTimeMax] = React.useState(queryTimeMax)

  React.useEffect(() => {
    errorRate = localErrorRate
    queryTimeMin = localFetchTimeMin
    queryTimeMax = localFetchTimeMax
  }, [localErrorRate, localFetchTimeMax, localFetchTimeMin])

  React.useEffect(() => {
    queryClient.setDefaultOptions({
      queries: {
        staleTime,
        cacheTime,
      },
    })
  }, [cacheTime, staleTime])

  return (
    <QueryClientProvider client={queryClient}>
      <p>
        The "staleTime" and "cacheTime" durations have been altered in this
        example to show how query stale-ness and query caching work on a
        granular level
      </p>
      <div>
        Stale Time:{' '}
        <input
          type="number"
          min="0"
          step="1000"
          value={staleTime}
          onChange={(e) => setStaleTime(parseFloat(e.target.value, 10))}
          style={{ width: '100px' }}
        />
      </div>
      <div>
        Cache Time:{' '}
        <input
          type="number"
          min="0"
          step="1000"
          value={cacheTime}
          onChange={(e) => setCacheTime(parseFloat(e.target.value, 10))}
          style={{ width: '100px' }}
        />
      </div>
      <br />
      <div>
        Error Rate:{' '}
        <input
          type="number"
          min="0"
          max="1"
          step=".05"
          value={localErrorRate}
          onChange={(e) => setErrorRate(parseFloat(e.target.value, 10))}
          style={{ width: '100px' }}
        />
      </div>
      <div>
        Fetch Time Min:{' '}
        <input
          type="number"
          min="1"
          step="500"
          value={localFetchTimeMin}
          onChange={(e) => setLocalFetchTimeMin(parseFloat(e.target.value, 10))}
          style={{ width: '60px' }}
        />{' '}
      </div>
      <div>
        Fetch Time Max:{' '}
        <input
          type="number"
          min="1"
          step="500"
          value={localFetchTimeMax}
          onChange={(e) => setLocalFetchTimeMax(parseFloat(e.target.value, 10))}
          style={{ width: '60px' }}
        />
      </div>
      <br />
      <App />
      <br />
      <ReactQueryDevtools initialIsOpen />
    </QueryClientProvider>
  )
}

function App() {
  const queryClient = useQueryClient()
  const [editingIndex, setEditingIndex] = React.useState(null)
  const [views, setViews] = React.useState(['', 'fruit', 'grape'])
  // const [views, setViews] = React.useState([""]);

  return (
    <div className="App">
      <div>
        <button onClick={() => queryClient.invalidateQueries()}>
          Force Refetch All
        </button>
      </div>
      <br />
      <hr />
      {views.map((view, index) => (
        <div key={index}>
          <Todos
            initialFilter={view}
            setEditingIndex={setEditingIndex}
            onRemove={() => {
              setViews((old) => [...old, ''])
            }}
          />
          <br />
        </div>
      ))}
      <button
        onClick={() => {
          setViews((old) => [...old, ''])
        }}
      >
        Add Filter List
      </button>
      <hr />
      {editingIndex !== null ? (
        <>
          <EditTodo
            editingIndex={editingIndex}
            setEditingIndex={setEditingIndex}
          />
          <hr />
        </>
      ) : null}
      <AddTodo />
    </div>
  )
}

function Todos({ initialFilter = '', setEditingIndex }) {
  const [filter, setFilter] = React.useState(initialFilter)

  const { status, data, isFetching, error, failureCount, refetch } = useQuery({
    queryKey: ['todos', { filter }],
    queryFn: fetchTodos,
  })

  return (
    <div>
      <div>
        <label>
          Filter:{' '}
          <input value={filter} onChange={(e) => setFilter(e.target.value)} />
        </label>
      </div>
      {status === 'loading' ? (
        <span>Loading... (Attempt: {failureCount + 1})</span>
      ) : status === 'error' ? (
        <span>
          Error: {error.message}
          <br />
          <button onClick={() => refetch()}>Retry</button>
        </span>
      ) : (
        <>
          <ul>
            {data
              ? data.map((todo) => (
                  <li key={todo.id}>
                    {todo.name}{' '}
                    <button onClick={() => setEditingIndex(todo.id)}>
                      Edit
                    </button>
                  </li>
                ))
              : null}
          </ul>
          <div>
            {isFetching ? (
              <span>
                Background Refreshing... (Attempt: {failureCount + 1})
              </span>
            ) : (
              <span>&nbsp;</span>
            )}
          </div>
        </>
      )}
    </div>
  )
}

function EditTodo({ editingIndex, setEditingIndex }) {
  const queryClient = useQueryClient()

  // Don't attempt to query until editingIndex is truthy
  const { status, data, isFetching, error, failureCount, refetch } = useQuery({
    queryKey: ['todo', { id: editingIndex }],
    queryFn: () => fetchTodoById({ id: editingIndex }),
    enabled: editingIndex !== null,
  })

  const [todo, setTodo] = React.useState(data || {})

  React.useEffect(() => {
    if (editingIndex !== null && data) {
      setTodo(data)
    } else {
      setTodo({})
    }
  }, [data, editingIndex])

  const saveMutation = useMutation({
    mutationFn: patchTodo,
    onSuccess: (data) => {
      // Update `todos` and the individual todo queries when this mutation succeeds
      queryClient.invalidateQueries({ queryKey: ['todos'] })
      queryClient.setQueryData(['todo', { id: editingIndex }], data)
    },
  })

  const onSave = () => {
    saveMutation.mutate(todo)
  }

  const disableEditSave =
    status === 'loading' || saveMutation.status === 'loading'

  return (
    <div>
      <div>
        {data ? (
          <>
            <button onClick={() => setEditingIndex(null)}>Back</button> Editing
            Todo "{data.name}" (#
            {editingIndex})
          </>
        ) : null}
      </div>
      {status === 'loading' ? (
        <span>Loading... (Attempt: {failureCount + 1})</span>
      ) : error ? (
        <span>
          Error! <button onClick={() => refetch()}>Retry</button>
        </span>
      ) : (
        <>
          <label>
            Name:{' '}
            <input
              value={todo.name}
              onChange={(e) =>
                e.persist() ||
                setTodo((old) => ({ ...old, name: e.target.value }))
              }
              disabled={disableEditSave}
            />
          </label>
          <label>
            Notes:{' '}
            <input
              value={todo.notes}
              onChange={(e) =>
                e.persist() ||
                setTodo((old) => ({ ...old, notes: e.target.value }))
              }
              disabled={disableEditSave}
            />
          </label>
          <div>
            <button onClick={onSave} disabled={disableEditSave}>
              Save
            </button>
          </div>
          <div>
            {saveMutation.status === 'loading'
              ? 'Saving...'
              : saveMutation.status === 'error'
              ? saveMutation.error.message
              : 'Saved!'}
          </div>
          <div>
            {isFetching ? (
              <span>
                Background Refreshing... (Attempt: {failureCount + 1})
              </span>
            ) : (
              <span>&nbsp;</span>
            )}
          </div>
        </>
      )}
    </div>
  )
}

function AddTodo() {
  const queryClient = useQueryClient()
  const [name, setName] = React.useState('')

  const addMutation = useMutation({
    mutationFn: postTodo,
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['todos'] })
    },
  })

  return (
    <div>
      <input
        value={name}
        onChange={(e) => setName(e.target.value)}
        disabled={addMutation.status === 'loading'}
      />
      <button
        onClick={() => {
          addMutation.mutate({ name })
        }}
        disabled={addMutation.status === 'loading' || !name}
      >
        Add Todo
      </button>
      <div>
        {addMutation.status === 'loading'
          ? 'Saving...'
          : addMutation.status === 'error'
          ? addMutation.error.message
          : 'Saved!'}
      </div>
    </div>
  )
}

function fetchTodos({ signal, queryKey: [, { filter }] }) {
  console.info('fetchTodos', { filter })

  if (signal) {
    signal.addEventListener('abort', () => {
      console.info('cancelled', filter)
    })
  }

  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(
          new Error(JSON.stringify({ fetchTodos: { filter } }, null, 2)),
        )
      }
      resolve(list.filter((d) => d.name.includes(filter)))
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

function fetchTodoById({ id }) {
  console.info('fetchTodoById', { id })
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(
          new Error(JSON.stringify({ fetchTodoById: { id } }, null, 2)),
        )
      }
      resolve(list.find((d) => d.id === id))
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

function postTodo({ name, notes }) {
  console.info('postTodo', { name, notes })
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(
          new Error(JSON.stringify({ postTodo: { name, notes } }, null, 2)),
        )
      }
      const todo = { name, notes, id: id++ }
      list = [...list, todo]
      resolve(todo)
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

function patchTodo(todo) {
  console.info('patchTodo', todo)
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (Math.random() < errorRate) {
        return reject(new Error(JSON.stringify({ patchTodo: todo }, null, 2)))
      }
      list = list.map((d) => {
        if (d.id === todo.id) {
          return todo
        }
        return d
      })
      resolve(todo)
    }, queryTimeMin + Math.random() * (queryTimeMax - queryTimeMin))
  })
}

const rootElement = document.getElementById('root')
ReactDOM.createRoot(rootElement).render(<Root />)