old_contents: import chalk from 'chalk'
  import coolTrim from 'cool-trim'
  import { createServer } from 'spa-http-server'
  import { buildPath } from '../../path'
  
  export default function (host, port) {
    // Used with `app.listen` below
    const listenAddr = [port]
  
    if (host) {
      listenAddr.push(host)
    }
  
    const server = createServer({
      root: buildPath,
      pushState: true
    })
  
    return Promise.promisify(server.listen, { context: server })(
      ...listenAddr
    ).then(() => {
      const address = `http://${host || '127.0.0.1'}:${port}/`
  
      console.log(
        coolTrim`${chalk.green('Test server started on:')} ${chalk.yellow(address)}`
      )
  
      return Promise.resolve(address)
    })
  }
  
new_contents: import chalk from 'chalk'
  import coolTrim from 'cool-trim'
  import { createServer } from 'spa-http-server'
  import { buildPath } from '../../path'
  
  export default function (host, port) {
    const listenAddr = [port]
  
    if (host) {
      listenAddr.push(host)
    }
  
    const server = createServer({
      root: buildPath,
      pushState: true
    })
  
    return Promise.promisify(server.listen, { context: server })(
      ...listenAddr
    ).then(() => {
      const address = `http://${host || '127.0.0.1'}:${port}/`
  
      console.log(
        coolTrim`${chalk.green('Test server started on:')} ${chalk.yellow(address)}`
      )
  
      return Promise.resolve(address)
    })
  }
  
subject: remove unnecessary comment