vue-cli/packages/@vue/cli-service/lib/commands/build.js

const defaults = {
  mode: 'production',
  target: 'app'
}

module.exports = (api, options) => {
  api.registerCommand('build', {
    description: 'build for production',
    usage: 'vue-cli-service build [options]',
    options: {
      '--mode': `specify env mode (default: ${defaults.mode})`
      // TODO build target
      // '--target': `app | library | web-component (default: ${defaults.target})`
    }
  }, args => {
    api.setMode(args.mode || defaults.mode)

    const chalk = require('chalk')
    const rimraf = require('rimraf')
    const webpack = require('webpack')
    const {
      done,
      info,
      logWithSpinner,
      stopSpinner
    } = require('@vue/cli-shared-utils')

    console.log()
    logWithSpinner(`Building for production...`)

    return new Promise((resolve, reject) => {
      const targetDir = api.resolve(options.outputDir)
      rimraf(targetDir, err => {
        if (err) {
          return reject(err)
        }
        const webpackConfig = api.resolveWebpackConfig()
        webpack(webpackConfig, (err, stats) => {
          stopSpinner(false)
          if (err) {
            return reject(err)
          }

          if (!args.silent) {
            process.stdout.write(stats.toString({
              colors: true,
              modules: false,
              children: api.hasPlugin('typescript'),
              chunks: false,
              chunkModules: false
            }) + '\n\n')
          }

          if (stats.hasErrors()) {
            return reject(`Build failed with errors.`)
          }

          if (!args.silent) {
            done(`Build complete. The ${chalk.cyan(options.outputDir)} directory is ready to be deployed.\n`)
            if (options.baseUrl === '/') {
              info(`The app is built assuming that it will be deployed at the root of a domain.`)
              info(`If you intend to deploy it under a subpath, update the ${chalk.green('base')} option`)
              info(`in your project config (${chalk.cyan(`vue.config.js`)} or ${chalk.green('"vue"')} field in ${chalk.cyan(`package.json`)}).\n`)
            }
            // TODO info(`You can view more deployment tips at ???`)
          }

          // test-only signal
          if (process.env.VUE_CLI_TEST) {
            console.log('Build complete.')
          }

          resolve()
        })
      })
    })
  })
}