next.js/packages/next/build/webpack/plugins/nextjs-ssr-import.js

import { join, resolve, relative, dirname } from 'path'

// This plugin modifies the require-ensure code generated by Webpack
// to work with Next.js SSR
export default class NextJsSsrImportPlugin {
  apply (compiler) {
    compiler.hooks.compilation.tap('NextJsSSRImport', (compilation) => {
      compilation.mainTemplate.hooks.requireEnsure.tap('NextJsSSRImport', (code, chunk) => {
        // Update to load chunks from our custom chunks directory
        const outputPath = resolve('/')
        const pagePath = join('/', dirname(chunk.name))
        const relativePathToBaseDir = relative(pagePath, outputPath)
        // Make sure even in windows, the path looks like in unix
        // Node.js require system will convert it accordingly
        const relativePathToBaseDirNormalized = relativePathToBaseDir.replace(/\\/g, '/')
        return code.replace('require("./"', `require("${relativePathToBaseDirNormalized}/"`).replace('readFile(join(__dirname', `readFile(join(__dirname, "${relativePathToBaseDirNormalized}"`)
      })
    })
  }
}