<p>vue-server-renderer: directiva no aplicada al componente importado</p>

¿Qué problema resuelve esta función?

Actualmente, las directivas SSR no se aplican a (sub) componentes usados, sino solo a etiquetas y elementos HTML.

Reproducción

// Step 1: Create a Vue instance
const Vue = require("vue");

const Test = {
  template: `<div>This should be red</div>`
}

const app = new Vue({
  template: `
  <div>
    <Test v-make-red/>
    <div v-make-red>This is red</div>
  </div>
  `,
  components: {
    Test
  }
});

const makeRed = (node, dir) => {
  const style = node.data.style || (node.data.style = {});
  if (Array.isArray(style)) {
    style.push({ backgroundColor: "red" });
  } else {
    style.backgroundColor = "red";
  }
};

// Step 2: Create a renderer
const renderer = require("vue-server-renderer").createRenderer({
  directives: {
    makeRed
  }
});

// Step 3: Render the Vue instance to HTML
renderer.renderToString(app, (err, html) => {
  if (err) throw err;
  console.log(html);
  // <div data-server-rendered="true"><div>This should be red</div> <div style="background-color:red;">This is red</div></div>
  // But should include red background-color style for the first div as well
});

Relacionado: https://github.com/nuxt/nuxt.js/issues/6575