const outlines = sites.filter(site => site.rss).map(site => {
  return `<outline type="rss" xmlUrl="${site.rss}" title="${site.title}"/>`
})

const template = `<?xml version="1.0" encoding="UTF-8"?><opml version="1.1"><head></head><body>${outlines.join('')}</body></opml>`

window.onload = function () {
  const a = document.getElementById('opml')
  if (a) {
    a.setAttribute('href', 'data:text/plain;charset=utf-8,' + window.encodeURIComponent(template))
    a.setAttribute('download', 'webring.opml')
  }
}