How to git pull before these actions (copy, add, commit, push)

[dimaslanjaka]

my deploy code, before executing below function, i executing copy (gulp copy)

ghpages.publish(
  destDir,
  {
    branch: 'gh-pages',
    dotfiles: true,
    message: 'update site ' + moment().format('LLL'),
    repo: pkg.repository.url
  },
  resolvePromise
)

how to pull before copying ? should i using spawn git ?, can i doing it with this library, without spawning git again ?