zoro-cli/lib/plugins/config-webpack/template/script/Configurator.js

https://github.com/vuejs/vue-cli

const debug = require('debug')('webpack-config')
const WebpackChain = require('webpack-chain')
const merge = require('webpack-merge')
const { defaultsDeep } = require('lodash')
const path = require('path')
const PluginAPI = require('./PluginAPI')
const { defaults } = require('./options')
const envUtil = require('./env')

function resolvePlugins() {
  /* eslint-disable import/no-dynamic-require */
  const idToPlugin = id => ({
    id: id.replace(/^.\//, 'plugin:'),
    apply: require(id),
  })
  /* eslint-enable import/no-dynamic-require */

  const plugins = [
    // config plugins are order sensitive
    './config/base',
    './config/eslint',
    './config/babel',
    './config/css',
    './config/dev',
    './config/prod',
    // app/lib should come at the end, since they may modify the above plugins
    './config/app',
    './config/lib',
  ].map(idToPlugin)

  return plugins
}

class Config {
  constructor(options = {}) {
    const { args = {} } = options
    this.context = process.cwd()
    this.webpackChainFns = []
    this.webpackRawConfigFns = []

    this.initPkg()
    this.initProjectOptions()

    this.plugins = resolvePlugins()
    this.plugins.forEach(({ id, apply }) => {
      apply({
        api: new PluginAPI(id, this),
        // 所有的配置统一合并在 options 里面
        options: {
          ...this.projectOptions,
          ...args,
        },
        envUtil,
        args,
        pkg: this.pkg,
      })
    })

    // apply webpack configs from project config file
    if (this.projectOptions.chainWebpack) {
      this.webpackChainFns.push(this.projectOptions.chainWebpack)
    }
    if (this.projectOptions.configureWebpack) {
      this.webpackRawConfigFns.push(this.projectOptions.configureWebpack)
    }
  }

  initPkg() {
    const pkgPath = path.join(this.context, 'package.json')
    /* eslint-disable import/no-dynamic-require */
    this.pkg = require(pkgPath)
    /* eslint-enable import/no-dynamic-require */
  }

  initProjectOptions() {
    let projectOptions = {}
    try {
      /* eslint-disable import/no-dynamic-require */
      projectOptions = require(path.join(this.context, 'project.config'))
      /* eslint-enable import/no-dynamic-require */
    } catch (e) {
      console.log('could not load project.config')
    }
    this.projectOptions = defaultsDeep(projectOptions, defaults())
    debug(this.projectOptions)
  }

  resolveChainableWebpackConfig() {
    const chainableConfig = new WebpackChain()
    // apply chains
    this.webpackChainFns.forEach(fn => fn(chainableConfig))
    return chainableConfig
  }

  resolveWebpackConfig(chainableConfig = this.resolveChainableWebpackConfig()) {
    // get raw config
    let config = chainableConfig.toConfig()
    // apply raw config fns
    this.webpackRawConfigFns.forEach(fn => {
      if (typeof fn === 'function') {
        // function with optional return value
        const res = fn(config)
        if (res) config = merge(config, res)
      } else if (fn) {
        // merge literal values
        config = merge(config, fn)
      }
    })
    return config
  }
}

module.exports = Config