Nodejs check file exists, if not, wait till it exist

Question

I\'m generating files automatically, and I have another script which will check if a given file is already generated, so how could I implement such a function:

f         


        

Answer 1

You could implement it like this if you have node 6 or higher.

const fs = require('fs')

function checkExistsWithTimeout(path, timeout) {
  return new Promise((resolve, reject) => {
    const timeoutTimerId = setTimeout(handleTimeout, timeout)
    const interval = timeout / 6
    let intervalTimerId

    function handleTimeout() {
      clearTimeout(timerId)

      const error = new Error('path check timed out')
      error.name = 'PATH_CHECK_TIMED_OUT'
      reject(error)
    }

    function handleInterval() {
      fs.access(path, (err) => {
        if(err) {
          intervalTimerId = setTimeout(handleInterval, interval)
        } else {
          clearTimeout(timeoutTimerId)
          resolve(path)
        }
      })
    }

    intervalTimerId = setTimeout(handleInterval, interval)
  })
}