我在工作中接到了一项提高项目绩效的任务。目前，Google Lighthouse 的得分会有所波动，但总体而言得分并不高，因此我们正在努力弄清楚如何提高其性能，以便向我们的领导层炫耀。

我们的项目将整个 Gatsby 站点作为单个 JavaScript 包加载。这会从站点创建一个单页应用程序，允许通过 JavaScript 快速加载新页面。但是对于像我们的 WordPress 网站一样大的东西，这会产生一个非常大的包，以兆字节为单位。这个大包显着降低了页面速度。

我不太确定如何卸载这个 bundle.js，但我发现了一个关于这个主题的有趣文档https://www.gatsbyjs.org/docs/how-code-splitting-works/

虽然我并不完全理解这些文档，但我相信我编辑了这个 async-requires.js 文件以包含多个导出组件行，这应该会导致多个 javascript 包而不是主要的大包。也许如果有多个 js 包，站点会加载得更快，因为它不仅仅是一个瓶颈。因此，页面可以加载到它需要呈现的特定包中，并异步加载它不需要的包。

下面是一些我认为与手头任务相关的代码。当谈到 gatsby 时，我仍然是一个初学者，所以我不确定我可以在这里改变什么来获得更好的性能。

感谢您的帮助。

异步-requires.js

const preferDefault = m => m && m.default || m

exports.components = {
  "component---src-templates-page-js": () => import("../src/templates/page.js" /* webpackChunkName: "component---src-templates-page-js" */),
  "component---cache-dev-404-page-js": () => import("dev-404-page.js" /* webpackChunkName: "component---cache-dev-404-page-js" */),
  "component---src-pages-404-js": () => import("../src/pages/404.js" /* webpackChunkName: "component---src-pages-404-js" */)
}

源代码/模板/pages.js

import React from 'react'
import PropTypes from 'prop-types'
import Helmet from 'react-helmet'
import Layout from '../layouts/layout'
import AnalyticsContext, { analyticsEvents } from '../../util/AnalyticsContext'

import Banner from '../WPComponents/Banner'
import CheckmarkList from '../WPComponents/CheckmarkList'
import CopyGrid from '../WPComponents/CopyGrid'
import Drawers from '../WPComponents/Drawers'
import Explainers from '../WPComponents/Explainers'
import Featured from '../WPComponents/Featured'
import Form from '../WPComponents/Form'
import Hero from '../WPComponents/Hero'
import Pricing from '../WPComponents/Pricing'
import PromoApp from '../WPComponents/PromoApp'
import PromoCircles from '../WPComponents/PromoCircles'
import PromoSlider from '../WPComponents/PromoSlider'
import ReachAnimation from '../WPComponents/ReachAnimation'
import Resources from '../WPComponents/Resources'
import SimpleExplainer from '../WPComponents/SimpleExplainer'
import SimpleMedia from '../WPComponents/SimpleMedia'
import Solution from '../WPComponents/Solution'
import Testimonials from '../WPComponents/Testimonials'
import Disclaimer from '../WPComponents/Disclaimer'

const PageTemplate = props => {
  const { pageContext, data, location } = props
  const components = (pageContext.acf && pageContext.acf.section_page) || []
  let helmet
  const { yoast } = pageContext

  if (yoast) {
    const {
      title,
      metadesc,
      opengraph_title,
      opengraph_description,
      opengraph_image,
      canonical,
    } = yoast

    helmet = (
      <Helmet
        title={title || ' '}
        meta={[
          {
            name: 'robots',
            content: 'noindex',
          },
          {
            name: 'description',
            content: metadesc || ' ',
          },
          {
            property: 'og:title',
            content: opengraph_title || ' ',
          },
          { property: 'og:site_name', content: title || ' ' },
          { property: 'og:type', content: 'website' },
          {
            property: 'og:description',
            content: opengraph_description || ' ',
          },
          {
            property: 'og:image',
            content: opengraph_image && opengraph_image.source_url,
          },
          canonical
            ? {
                property: 'og:url',
                content: canonical || ' ',
              }
            : {},
        ]}
      />
    )
  }

  return (
    <AnalyticsContext.Provider
      value={{
        ...analyticsEvents,
      }}
    >
      <Layout location={location}>
        {helmet}
        {components.map(component => {
          switch (component.__typename) {
            case 'WordPressAcf_hero':
              return <Hero key={component.id} {...component} />
            case 'WordPressAcf_featured':
              return <Featured key={component.id} {...component} />
            case 'WordPressAcf_solution':
              return <Solution key={component.id} {...component} />
            case 'WordPressAcf_resources':
              return <Resources key={component.id} {...component} />
            case 'WordPressAcf_simplemedia':
              return <SimpleMedia key={component.id} {...component} />
            case 'WordPressAcf_promoapp':
              return <PromoApp key={component.id} {...component} />
            case 'WordPressAcf_reach_animation':
              return <ReachAnimation key={component.id} {...component} />
            case 'WordPressAcf_promoslider':
              return <PromoSlider key={component.id} {...component} />
            case 'WordPressAcf_promocircles':
              return <PromoCircles key={component.id} {...component} />
            case 'WordPressAcf_testimonials':
              return <Testimonials key={component.id} {...component} />
            case 'WordPressAcf_banner':
              return <Banner key={component.id} {...component} />
            case 'WordPressAcf_explainers':
              return <Explainers key={component.id} {...component} />
            case 'WordPressAcf_copygrid':
              return <CopyGrid key={component.id} {...component} />
            case 'WordPressAcf_drawers':
              return <Drawers key={component.id} {...component} />
            case 'WordPressAcf_simpleexplainer':
              return <SimpleExplainer key={component.id} {...component} />
            case 'WordPressAcf_disclaimer':
              return <Disclaimer key={component.id} {...component} />
            case 'WordPressAcf_pricing':
              return (
                <Pricing key={component.id} {...component} /> 
              )
            case 'WordPressAcf_checkmarklist':
              return <CheckmarkList key={component.id} {...component} />
            case 'WordPressAcf_form':
              return <Form key={component.id} {...component} />
            default:
              console.log('Could not recongize type:', component.__typename)
              return
          }
        })}
      </Layout>
    </AnalyticsContext.Provider>
  )
}

PageTemplate.propTypes = {
  pageContext: PropTypes.shape({
    acf: PropTypes.object,
    media: PropTypes.shape({
      edges: PropTypes.array,
    }),
  }),
}

export default PageTemplate

pageCreators.js

const path = require('path')
const genericPageTemplate = 'src/templates/page.js'

const pageCreator = templatePath => (actions, pageContext) => {

  actions.createPage({
    component: path.resolve(templatePath),
    path: pageContext.pagePath,
    context: {
      ...pageContext,
    },
  })
}

module.exports = {
  createGenericPage: pageCreator(genericPageTemplate),
}

创建页面.js

const { createGenericPage } = require('./pageCreators')

const generatePages = allWordpressPage => {
  return allWordpressPage.edges.map(edge => edge.node)
}

module.exports = (data, actions) => {
  if (!data) {
    console.error('createPages()', 'Error', '`data` is undefined')
    throw new Error('Error retrieving data: data is undefined')
  }

  const { allWordpressPage } = data

  const pages = allWordpressPage && generatePages(allWordpressPage)

  if (!pages) {
    console.error(
      'createPages()',
      'Error',
      'Could not build pages. allWordpressPage was falsy'
    )
    throw new Error('Error retreiving data: allWordpressPage was falsy')
  }

  pages &&
    pages.forEach(page => {

      // skip the 'modules' page
      if (page.pagePath === '/modules/') {
        return;
      }

      createGenericPage(actions, page)
    })
}

gatsby-node.js

/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: https://www.gatsbyjs.org/docs/node-apis/
 */

const fs = require('fs')

const queryAll = require('./util/queryAll')
const createPages = require('./util/createPages')

exports.createPages = ({ graphql, actions }) => {
  return graphql(queryAll)
    .then(res => {
      if (res.errors) {
        res.errors.forEach(error => {
          console.error('Error:', error.message)
        })
      }

      createPages(res.data, actions)
    })
    .catch(error => {
      console.error('failed to create pages:', { error })
    })
}

exports.sourceNodes = ({ actions, schema }) => {
  const { createTypes } = actions

  const additionalTypeDefs = fs.readFileSync(`type-defs.gql`, {
    encoding: `utf-8`,
  })
  createTypes(additionalTypeDefs)
}

// temporary fix for dev env: https://github.com/gatsbyjs/gatsby/issues/11934#issuecomment-469046186
exports.onCreateWebpackConfig = ({ getConfig, stage }) => {
  const config = getConfig()
  if (stage.startsWith('develop') && config.resolve) {
    config.resolve.alias = {
      ...config.resolve.alias,
      'react-dom': '@hot-loader/react-dom',
    }
  }
}