webpack.gitinfo.js

// grab some info from git on the state of the repo
// https://isomorphic-git.org/docs/en/fs
const git = require('isomorphic-git')
const fs = require('fs')

async function tagsToCommits ({ dir }) {
  const map = {}

  const tags = await git.listTags({ fs, dir })
  for (const tag of tags) {
    const ref = await git.resolveRef({ fs, dir, ref: tag })
    map[tag] = ref
  }

  return map
}

async function tagsPointAt ({ dir, oid }) {
  const tagMap = await tagsToCommits({ dir })
  const pointAt =
    Object.entries(tagMap)
      .filter(([tag, commit]) => commit === oid)
      .map(([tag]) => tag)

  return pointAt
}

async function fetchGitInfo ({ ref, dir = '.' } = {}) {
  try {
    const [head] = await git.log({ fs, dir, depth: 1, ref })
    const tagsPointAtHead = await tagsPointAt({ dir, oid: head.oid })

    // https://isomorphic-git.org/docs/en/statusMatrix
    const fileStatus = (await git.statusMatrix({ fs, dir })).reduce((fs, file) => {
      fs.push({
        file: file[0],
        untracked: file[1] === 0 && file[2] === 2 && file[3] === 0,
        unmodified: file[1] === 1 && file[2] === 1 && file[3] === 1,
        staged: file[3] === 2 || file[3] === 3 || (file[1] === 1 && file[2] === 0 && file[3] === 0),
        modified: file[1] === 1 && file[2] === 2,
        deleted: file[1] === 1 && file[2] === 0,
        added: file[1] === 0 && file[2] === 2 && file[3] !== 0,
      })
      return fs
    }, [])

    const gitInfo = {
      headOid: head.oid.substr(0, 8),
      hasChanges: fileStatus.length !== fileStatus.filter(status => status.unmodified).length,
      isHeadOidTagged: tagsPointAtHead.length > 0,
      headTags: tagsPointAtHead,

      untracked: fileStatus.filter(status => status.untracked).length,
      staged: fileStatus.filter(status => status.staged).length,
      added: fileStatus.filter(status => status.added).length,
      modified: fileStatus.filter(status => status.modified).length,
      deleted: fileStatus.filter(status => status.deleted).length,
    }
    return gitInfo
  } catch (e) {
    if (e.name === 'ResolveRefError') {
      console.info('building from non-git repo')
    }
    return false
  }
}

module.exports = fetchGitInfo