Nuxt/lib/builder/webpack/plugins/vue/util.js

import chalk from 'chalk'

const prefix = `[vue-server-renderer-webpack-plugin]`
export const warn = msg => console.error(chalk.red(`${prefix} ${msg}\n`)) // eslint-disable-line no-console
export const tip = msg => console.log(chalk.yellow(`${prefix} ${msg}\n`)) // eslint-disable-line no-console

export const validate = compiler => {
  if (compiler.options.target !== 'node') {
    warn('webpack config `target` should be "node".')
  }

  if (compiler.options.output && compiler.options.output.libraryTarget !== 'commonjs2') {
    warn('webpack config `output.libraryTarget` should be "commonjs2".')
  }

  if (!compiler.options.externals) {
    tip(
      'It is recommended to externalize dependencies in the server build for ' +
      'better build performance.'
    )
  }
}

export const onEmit = (compiler, name, hook) => {
  if (compiler.hooks) {
    // Webpack >= 4.0.0
    compiler.hooks.emit.tapAsync(name, hook)
  } else {
    // Webpack < 4.0.0
    compiler.plugin('emit', hook)
  }
}

export const isJS = file => /\.js(\?[^.]+)?$/.test(file)

export const isCSS = file => /\.css(\?[^.]+)?$/.test(file)