incl. meta-description in seo.js (closes #1336)

[dhvenema]

No description provided.

[marcoscaceres]

As this is universally useful, we should make a new module ("core/seo"). Also, remember to only use "var" for global variables (basically never): always use const unless the variable is going to change , in which case you use let.

export async function run(conf, doc, cb) {
  const metaDescription = doc.querySelector("#abstract p:first-of-type");
  if (!metaDescription) {
    return; // no abstract, so abort early
  }
  // This is not critical, so let's continue other processing first:
  cb();
  await doc.respecIsReady;
  const metaElem = doc.createElement("meta");
  metaElem.name = "description";
  metaElem.content = metaDescription.textContent;
  doc.head.appendChild(metaElem);
}

[marcoscaceres]

Replaced by #1364