text: // Source: https://github.com/vuejs/vue/tree/dev/src/server/webpack-plugin/server.js
  
  const { validate, isJS, onEmit } = require("./util");
  
  class VueSSRServerPlugin {
    constructor(options = {}) {
      this.options = Object.assign(
        {
          filename: "vue-ssr-server-bundle.json",
        },
        options,
      );
    }
  
    apply(compiler) {
      validate(compiler);
  
      onEmit(compiler, "vue-server-plugin", (compilation, cb) => {
        const stats = compilation.getStats().toJson();
        const entryName = Object.keys(stats.entrypoints)[0];
        const entryInfo = stats.entrypoints[entryName];
  
        if (!entryInfo) {
          // #5553
          return cb();
        }
  
        const entryAssets = entryInfo.assets.filter(isJS);
  
        if (entryAssets.length > 1) {
          throw new Error(
            `Server-side bundle should have one single entry file. ` +
              `Avoid using CommonsChunkPlugin in the server config.`,
          );
        }
  
        const entry = entryAssets[0];
        if (!entry || typeof entry !== "string") {
          throw new Error(
            `Entry "${entryName}" not found. Did you specify the correct entry option?`,
          );
        }
  
        const bundle = {
          entry,
          files: {},
          maps: {},
        };
  
        stats.assets.forEach((asset) => {
          if (isJS(asset.name)) {
            bundle.files[asset.name] = compilation.assets[asset.name].source();
          } else if (asset.name.match(/\.js\.map$/)) {
            bundle.maps[asset.name.replace(/\.map$/, "")] = JSON.parse(
              compilation.assets[asset.name].source(),
            );
          }
          // do not emit anything else for server
          delete compilation.assets[asset.name];
        });
  
        const json = JSON.stringify(bundle, null, 2);
        const filename = this.options.filename;
  
        compilation.assets[filename] = {
          source: () => json,
          size: () => json.length,
        };
  
        cb();
      });
    }
  }
  
  module.exports = { VueSSRServerPlugin };
  