Cancellation with AbortController

Use case

Cancel in-flight requests -- for example, when a user navigates away or types a new search query.

Smallest working example

import { createClient } from '@parcely/core'

const http = createClient({ baseURL: 'https://api.example.com' })

const controller = new AbortController()

// Start the request
const promise = http.get('/search', {
  params: { q: 'hello' },
  signal: controller.signal,
})

// Cancel it
controller.abort()

When aborted, the request throws HttpError with code: 'ERR_ABORTED'.

Handling cancellation

import { isHttpError } from '@parcely/core'

try {
  await http.get('/data', { signal: controller.signal })
} catch (err) {
  if (isHttpError(err) && err.code === 'ERR_ABORTED') {
    console.log('Request was cancelled')
  }
}

React example: cancel on unmount

import { useEffect, useState } from 'react'
import { createClient } from '@parcely/core'

const http = createClient({ baseURL: 'https://api.example.com' })

function UserProfile({ userId }: { userId: string }) {
  const [user, setUser] = useState(null)

  useEffect(() => {
    const controller = new AbortController()
    http.get(`/users/${userId}`, { signal: controller.signal })
      .then((res) => setUser(res.data))
      .catch(() => {})
    return () => controller.abort()
  }, [userId])

  return user ? <div>{user.name}</div> : <div>Loading...</div>
}

Axios equivalent

// axios (modern):
const controller = new AbortController()
await http.get('/data', { signal: controller.signal })
controller.abort()

// parcely (identical):
const controller2 = new AbortController()
await http.get('/data', { signal: controller2.signal })
controller2.abort()

parcely does not support the legacy axios CancelToken API. Use AbortController instead.

Notes and gotchas

• The signal option accepts any AbortSignal.
• If both signal and timeout are set, they are combined via AbortSignal.any. A user abort produces ERR_ABORTED; a timeout produces ERR_TIMEOUT.
• After abort, the response body is consumed/discarded to prevent resource leaks.