git-updates.js

import { exec } from 'child_process'
import debug from 'debug'

export default {
  check: cwd => new Promise((resolve, reject) => {
    let resolveObj = {
      behind: false,
      amount: 0,
      branch: 'origin/stable'
    }
    const git = exec('git fetch && git status', { cwd })
    
    const checkOutput = data => {
      const isBehind = data.match(/Your branch is behind '(.+)' by (\d) commit/)
      const isCurrent = data.match(/Your branch is up-to-date with '(.+)'/)
      if (isBehind && isBehind.length > 1) {
        const [,branch,amount] = isBehind
        resolveObj = { behind: true, branch, amount }
      }
      if (isCurrent && isCurrent.length > 1) {
        const [,branch] = isCurrent
        resolveObj = { ...resolveObj, branch }
      }
    }
    git.stdout.on('data', checkOutput)
    git.stderr.on('data', checkOutput)
    git.on('exit', code => {
      if (code === 0 || code === '0') {
        debug.log('Done checking for updates')
        return resolve(resolveObj)
      } else {
        debug.log('Checking for updates failed')
        return reject(new Error(`git exited with status code ${code}`)
      }
    })
  }),

  update: cwd => new Promise((resolve, reject) => {
    const git = exec('git pull', { cwd })
    const log = data => debug.log(data)
    git.stdout.on('data', log)
    git.stderr.on('data', log)
    git.on('exit', code => {
      if (code === 0 || code === '0') {
        debug.log('Update successful')
        return resolve()
      } else {
        debug.log('Update failed')
        return reject(new Error(`git exited with status code ${code}`))
      }
    })
  })
}