rsnext/packages/next/build/webpack/loaders/next-plugin-loader.ts

import { loader } from 'webpack'
import { parse } from 'querystring'
import { PluginMetaData, getPluginId } from '../../plugins/collect-plugins'

export type NextPluginLoaderQuery = {
  middleware: string
}

export const pluginLoaderOptions: {
  plugins: PluginMetaData[]
} = {
  plugins: [],
}

const nextPluginLoader: loader.Loader = function () {
  const { middleware }: NextPluginLoaderQuery =
    typeof this.query === 'string' ? parse(this.query.substr(1)) : this.query

  const plugins = pluginLoaderOptions.plugins.filter((plugin) => {
    return plugin.middleware.includes(middleware)
  })

  const pluginIds: string[] = []
  const pluginConfigs: any[] = []

  return `
    ${plugins
      .map((plugin) => {
        const pluginId = getPluginId(plugin.pkgName)
        pluginIds.push(pluginId)
        pluginConfigs.push(plugin.config || {})
        return `import ${pluginId} from '${plugin.directory}/src/${middleware}'`
      })
      .join('\n')}

    export default function (ctx) {
      return Promise.all([${pluginIds
        .map((id, idx) => `${id}(ctx, ${JSON.stringify(pluginConfigs[idx])})`)
        .join(',')}])
    }
  `
}

export default nextPluginLoader