vuepress/packages/@vuepress/core/lib/webpack/DevLogPlugin.js

const { chalk, logger } = require('@vuepress/shared-utils')

module.exports = class DevLogPlugin {
  constructor (options) {
    this.options = options
  }

  apply (compiler) {
    let isFirst = true
    compiler.hooks.done.tap('vuepress-log', stats => {
      clearScreen()

      const { displayHost, port, publicPath } = this.options
      const time = new Date().toTimeString().match(/^[\d:]+/)[0]
      const displayUrl = `http://${displayHost}:${port}${publicPath}`

      logger.success(
        `\n${chalk.gray(`[${time}]`)} Build ${chalk.italic(stats.hash.slice(0, 6))} ` +
        `finished in ${stats.endTime - stats.startTime} ms! ` +
        (
          isFirst
            ? ''
            : `${chalk.gray(`(${displayUrl})`)}`
        )
      )
      if (isFirst) {
        isFirst = false
        console.log(`\n${chalk.gray('>')} VuePress dev server listening at ${chalk.cyan(displayUrl)}`)
      }
    })
    compiler.hooks.invalid.tap('vuepress-log', clearScreen)
  }
}

function clearScreen () {
  process.stdout.write('\x1Bc')
}