index.js

const workboxPlugin = require('workbox-webpack-plugin')

const defaultGenerateConfig = {
  exclude: [/\.map$/, /^(?:asset-)manifest.*\.js(?:on)?$/],
  navigateFallback: '/index.html',
  navigateFallbackBlacklist: [
    new RegExp('^/__'),
    new RegExp('/[^/]+\.[^/]+$'),
  ],
  clientsClaim: true
}

const defaultInjectConfig = {
  exclude: defaultGenerateConfig.exclude
}

function findSWPrecachePlugin(element) {
  return element.constructor.name === 'SWPrecacheWebpackPlugin'
}

function removeSWPrecachePlugin(config) {
  const swPrecachePluginIndex = config.plugins.findIndex(findSWPrecachePlugin)
  // Remove the swPrecachePlugin if it was found
  if (swPrecachePluginIndex !== -1) {
    config.plugins.splice(swPrecachePluginIndex, 1) // mutates
  }
}

function rewireWorkboxGenerate(workboxConfig) {
  workboxConfig = workboxConfig || defaultGenerateConfig
  return function rewireWorkboxInner(config, env) {
    removeSWPrecachePlugin(config)

    // Add the Workbox plugin
    config.plugins.push(new workboxPlugin.GenerateSW(workboxConfig))

    return config
  }
}

function rewireWorkboxInject(workboxConfig) {
  workboxConfig = workboxConfig || defaultInjectConfig
  return function rewireWorkboxInner(config, env) {
    removeSWPrecachePlugin(config)

    // Add the Workbox plugin
    config.plugins.push(new workboxPlugin.InjectManifest(workboxConfig))

    return config
  }
}

module.exports = {
  rewireWorkboxGenerate,
  rewireWorkboxInject,
  defaultGenerateConfig,
  defaultInjectConfig
}