either preload OR inline CSS (#6009)

* either preload OR inline

* Make sure all assets added

packages/gatsby/src/cache-dir/static-entry.js

@@ -168,6 +168,10 @@ export default (pagePath, callback) => {
  return { rel: `preload`, name: chunk }
  })
 
+ namedChunkGroups[s].assets.forEach(asset =>
+ chunks.push({ rel: `preload`, name: asset })
+ )
+
  const childAssets = namedChunkGroups[s].childAssets
  for (const rel in childAssets) {
  chunks = merge(
@@ -239,28 +243,32 @@ export default (pagePath, callback) => {
  .slice(0)
  .reverse()
  .forEach(style => {
- // Add <link>s for styles.
- headComponents.push(
- <link
- as="style"
- rel={style.rel}
- key={style.name}
- href={urlJoin(pathPrefix, style.name)}
- />
- )
-
- headComponents.unshift(
- <style
- type="text/css"
- data-href={urlJoin(pathPrefix, style.name)}
- dangerouslySetInnerHTML={{
- __html: fs.readFileSync(
- join(process.cwd(), `public`, style.name),
- `utf-8`
- ),
- }}
- />
- )
+ // Add <link>s for styles that should be prefetched
+ // otherwise, inline as a <style> tag
+
+ if (style.rel === `prefetch`) {
+ headComponents.push(
+ <link
+ as="style"
+ rel={style.rel}
+ key={style.name}
+ href={urlJoin(pathPrefix, style.name)}
+ />
+ )
+ } else {
+ headComponents.unshift(
+ <style
+ type="text/css"
+ data-href={urlJoin(pathPrefix, style.name)}
+ dangerouslySetInnerHTML={{
+ __html: fs.readFileSync(
+ join(process.cwd(), `public`, style.name),
+ `utf-8`
+ ),
+ }}
+ />
+ )
+ }
  })
 
  // Add page metadata for the current page