const gs = require('ghostscript-js')
gs.exec([
  '-q',
  '-dNOPAUSE',
  '-dBATCH',
  '-sDEVICE=tiff24nc',
  '-r300',
  '-sOutputFile=output-%03d.tiff',
  'input.pdf'
], (codeError) => {
  if (codeError) {
    // deal with the codeError
    ...
  } else {
    // Great ! No errors !
    ...
  }
});