@mishguru/cancel-token

Cancel Token for Promises

APT

CancelTokenSource

• cancel(reason)
• token

CancelToken

• #source()
• promise
• isCancelled()
• throwIfRequested()

Usage

Example of cancelling an HTTP request

const get = async (url: string, cancelToken: CancelToken): Promise<string> => {
  // check to see if the token is cancelled before the requests starts
  cancelToken.throwIfRequested()

  return new Promise((resolve, reject) => {
    // download a url async
    const request = https.get(url, (response) => {
      let body = ''
      response.setEncoding('utf8')
      response.on('data', (chunk) => (body += chunk))
      response.on('end', () => resolve(body))
      response.on('error', reject)
    })
    request.on('error', reject)

    // watch if the token gets cancelled, and cleanup
    cancelToken.promise.then((error) => {
      reject(error)
      request.abort()
    })
  })
}

Cancelling a Function

import CancelToken from '@mishguru/cancel-token'

// create CancelToken Source
const source = CancelToken.source()

// use canceltoken
get('https://api.mish.guru/info.json', source.token).then(console.log)

// cancel it
source.cancel(new Error('We no longer need info'))

references

• This project is a fork of miniprogram-cancel-token