git.version.ts

import { writeFileSync } from 'fs'
import { dedent } from 'tslint/lib/utils'

const util = require('util')
const exec = util.promisify(require('child_process').exec)

async function createVersionsFile(filename: string) {
  const revision = (await exec('git rev-parse --short HEAD')).stdout
    .toString()
    .trim()
  const branch = (await exec('git rev-parse --abbrev-ref HEAD')).stdout
    .toString()
    .trim()

  console.log(
    `version: '${process.env.npm_package_version}', revision: '${revision}', branch: '${branch}'`
  )

  const content = dedent`
      // this file is automatically generated by git.version.ts script
      export const versions = {
        version: '${process.env.npm_package_version}',
        revision: '${revision}',
        branch: '${branch}'
      }`

  writeFileSync(filename, content, { encoding: 'utf8' })
}

createVersionsFile('src/environments/versions.ts')