I tried this script below using Node8.x.
It worked but the size of the downloaded file was imperfect.
I tried for some time and each downloaded file size was not the same.
Using Node9+ I could download the file successfully.
Could anyone explain what was the cause?

  (async () => {
    const path = require('path')
    await downloadPromise(
      'http://yann.lecun.com/exdb/mnist/t10k-labels-idx1-ubyte.gz',
      path.join(__dirname, './', 't10k-labels-idx1-ubyte.gz'))
  })()

  function downloadPromise (url, savepath) {
    return new Promise((resolve, reject) => {
      const http = require('http')
      const fs = require('fs')
      const outfile = fs.createWriteStream(savepath)
      http.get(url, (res) => {
        res.pipe(outfile)
        res.on('end', () => {
          outfile.close()
          resolve()
        })
      })
      .on('error', (err) => reject(err))
    })
  }