Extract Astro styles to external stylesheets (#43)

* Extract Astro styles to external stylesheets

* Require relative URLs in Markdown layouts

3 files changed, 41 insertions, 44 deletions

diff --git a/src/compiler/codegen.ts b/src/compiler/codegen.ts
index 70620111d..63fc44dfb 100644
--- a/src/compiler/codegen.ts
+++ b/src/compiler/codegen.ts
@@ -21,7 +21,7 @@ interface Attribute {
   end: number;
   type: 'Attribute';
   name: string;
-  value: any;
+  value: TemplateNode[] | boolean;
 }
 
 interface CodeGenOptions {
@@ -41,7 +41,8 @@ function getAttributes(attrs: Attribute[]): Record<string, string> {
       result[attr.name] = JSON.stringify(attr.value);
       continue;
     }
-    if (attr.value === false) {
+    if (attr.value === false || attr.value === undefined) {
+      // note: attr.value shouldn’t be `undefined`, but a bad transform would cause a compile error here, so prevent that
       continue;
     }
     if (attr.value.length > 1) {
@@ -59,7 +60,7 @@ function getAttributes(attrs: Attribute[]): Record<string, string> {
         ')';
       continue;
     }
-    const val: TemplateNode = attr.value[0];
+    const val = attr.value[0];
     if (!val) {
       result[attr.name] = '(' + val + ')';
       continue;
@@ -72,7 +73,7 @@ function getAttributes(attrs: Attribute[]): Record<string, string> {
         result[attr.name] = JSON.stringify(getTextFromAttribute(val));
         continue;
       default:
-        throw new Error('UNKNOWN V');
+        throw new Error(`UNKNOWN: ${val.type}`);
     }
   }
   return result;
@@ -253,7 +254,7 @@ async function acquireDynamicComponentImports(plugins: Set<ValidExtensionPlugins
   return importMap;
 }
 
-export async function codegen(ast: Ast, { compileOptions, filename }: CodeGenOptions): Promise<TransformResult> {
+export async function codegen(ast: Ast, { compileOptions, filename, fileID }: CodeGenOptions): Promise<TransformResult> {
   const { extensions = defaultExtensions, astroConfig } = compileOptions;
   await eslexer.init;
 
@@ -334,6 +335,21 @@ export async function codegen(ast: Ast, { compileOptions, filename }: CodeGenOpt
   let collectionItem: JsxItem | undefined;
   let currentItemName: string | undefined;
   let currentDepth = 0;
+  let css: string[] = [];
+
+  walk(ast.css, {
+    enter(node: TemplateNode) {
+      if (node.type === 'Style') {
+        css.push(node.content.styles); // if multiple <style> tags, combine together
+        this.skip();
+      }
+    },
+    leave(node: TemplateNode) {
+      if (node.type === 'Style') {
+        this.remove(); // this will be optimized in a global CSS file; remove so it‘s not accidentally inlined
+      }
+    },
+  });
 
   walk(ast.html, {
     enter(node: TemplateNode) {
@@ -419,9 +435,9 @@ export async function codegen(ast: Ast, { compileOptions, filename }: CodeGenOpt
           return;
         }
         case 'Style': {
-          const attributes = getAttributes(node.attributes);
-          items.push({ name: 'style', jsx: `h("style", ${attributes ? generateAttributes(attributes) : 'null'}, ${JSON.stringify(node.content.styles)})` });
-          break;
+          css.push(node.content.styles); // if multiple <style> tags, combine together
+          this.skip();
+          return;
         }
         case 'Text': {
           const text = getTextFromAttribute(node);
@@ -469,6 +485,7 @@ export async function codegen(ast: Ast, { compileOptions, filename }: CodeGenOpt
           }
           return;
         case 'Style': {
+          this.remove(); // this will be optimized in a global CSS file; remove so it‘s not accidentally inlined
           return;
         }
         default:
@@ -481,5 +498,6 @@ export async function codegen(ast: Ast, { compileOptions, filename }: CodeGenOpt
     script: script,
     imports: Array.from(importExportStatements),
     items,
+    css: css.length ? css.join('\n\n') : undefined,
   };
 }
diff --git a/src/compiler/index.ts b/src/compiler/index.ts
index 8104ef4b4..1afa97c87 100644
--- a/src/compiler/index.ts
+++ b/src/compiler/index.ts
@@ -10,7 +10,6 @@ import { CompileResult, TransformResult } from '../@types/astro';
 import { parse } from '../parser/index.js';
 import { createMarkdownHeadersCollector } from '../micromark-collect-headers.js';
 import { encodeMarkdown } from '../micromark-encode.js';
-import { defaultLogOptions } from '../logger.js';
 import { optimize } from './optimize/index.js';
 import { codegen } from './codegen.js';
 
@@ -75,14 +74,14 @@ async function convertMdToJsx(
 
   const raw = `---
   ${imports}
-  ${frontmatterData.layout ? `export const __layout = ${JSON.stringify(frontmatterData.layout)};` : ''}
+  ${frontmatterData.layout ? `import {__renderPage as __layout} from '${frontmatterData.layout}';` : 'const __layout = undefined;'}
   export const __content = ${stringifiedSetupContext};
 ---
 <section>${mdHtml}</section>`;
 
   const convertOptions = { compileOptions, filename, fileID };
 
-  return convertAstroToJsx(raw, convertOptions);
+  return await convertAstroToJsx(raw, convertOptions);
 }
 
 type SupportedExtensions = '.astro' | '.md';
@@ -94,9 +93,9 @@ async function transformFromSource(
   const fileID = path.relative(projectRoot, filename);
   switch (path.extname(filename) as SupportedExtensions) {
     case '.astro':
-      return convertAstroToJsx(contents, { compileOptions, filename, fileID });
+      return await convertAstroToJsx(contents, { compileOptions, filename, fileID });
     case '.md':
-      return convertMdToJsx(contents, { compileOptions, filename, fileID });
+      return await convertMdToJsx(contents, { compileOptions, filename, fileID });
     default:
       throw new Error('Not Supported!');
   }
@@ -108,8 +107,6 @@ export async function compileComponent(
 ): Promise<CompileResult> {
   const sourceJsx = await transformFromSource(source, { compileOptions, filename, projectRoot });
   const isPage = path.extname(filename) === '.md' || sourceJsx.items.some((item) => item.name === 'html');
-  // sort <style> tags first
-  sourceJsx.items.sort((a, b) => (a.name === 'style' && b.name !== 'style' ? -1 : 0));
 
   // return template
   let modJsx = `
@@ -144,8 +141,7 @@ export async function __renderPage({request, children, props}) {
 
   // find layout, if one was given.
   if (currentChild.layout) {
-    const layoutComponent = (await import('/_astro/layouts/' + currentChild.layout.replace(/.*layouts\\//, "").replace(/\.astro$/, '.js')));
-    return layoutComponent.__renderPage({
+    return currentChild.layout({
       request,
       props: {content: currentChild.content},
       children: [childBodyResult],
@@ -162,5 +158,6 @@ export async function __renderPage() { throw new Error("No <html> page element f
   return {
     result: sourceJsx,
     contents: modJsx,
+    css: sourceJsx.css,
   };
 }
diff --git a/src/compiler/optimize/styles.ts b/src/compiler/optimize/styles.ts
index fa32445ba..b833f9e70 100644
--- a/src/compiler/optimize/styles.ts
+++ b/src/compiler/optimize/styles.ts
@@ -26,7 +26,7 @@ const getStyleType: Map<string, StyleType> = new Map([
 ]);
 
 const SASS_OPTIONS: Partial<sass.Options> = {
-  outputStyle: 'compressed',
+  outputStyle: process.env.NODE_ENV === 'production' ? 'compressed' : undefined,
 };
 /** HTML tags that should never get scoped classes */
 const NEVER_SCOPED_TAGS = new Set<string>(['html', 'head', 'body', 'script', 'style', 'link', 'meta']);
@@ -95,11 +95,10 @@ async function transformStyle(code: string, { type, filename, scopedClass }: { t
   return { css, type: styleType };
 }
 
+/** Style optimizer */
 export default function ({ filename, fileID }: { filename: string; fileID: string }): Optimizer {
   const styleNodes: TemplateNode[] = []; // <style> tags to be updated
   const styleTransformPromises: Promise<StyleTransformResult>[] = []; // async style transform results to be finished in finalize();
-  let rootNode: TemplateNode; // root node which needs <style> tags
-
   const scopedClass = `astro-${hashFromFilename(fileID)}`; // this *should* generate same hash from fileID every time
 
   return {
@@ -124,15 +123,7 @@ export default function ({ filename, fileID }: { filename: string; fileID: strin
               return;
             }
 
-            // 2. find the root node to inject the <style> tag in later
-            // TODO: remove this when we are injecting <link> tags into <head>
-            if (node.name === 'head') {
-              rootNode = node; // If this is <head>, this is what we want. Always take this if found. However, this may not always exist (it won’t for Component subtrees).
-            } else if (!rootNode) {
-              rootNode = node; // If no <head> (yet), then take the first element we come to and assume it‘s the “root” (but if we find a <head> later, then override this per the above)
-            }
-
-            // 3. add scoped HTML classes
+            // 2. add scoped HTML classes
             if (NEVER_SCOPED_TAGS.has(node.name)) return; // only continue if this is NOT a <script> tag, etc.
             // Note: currently we _do_ scope web components/custom elements. This seems correct?
 
@@ -175,10 +166,6 @@ export default function ({ filename, fileID }: { filename: string; fileID: strin
                 scopedClass,
               })
             );
-
-            // TODO: we should delete the old untransformed <style> node after we’re done.
-            // However, the svelte parser left it in ast.css, not ast.html. At the final step, this just gets ignored, so it will be deleted, in a sense.
-            // If we ever end up scanning ast.css for something else, then we’ll need to actually delete the node (or transform it to the processed version)
           },
         },
       },
@@ -186,14 +173,9 @@ export default function ({ filename, fileID }: { filename: string; fileID: strin
     async finalize() {
       const styleTransforms = await Promise.all(styleTransformPromises);
 
-      if (!rootNode) {
-        throw new Error(`No root node found`); // TODO: remove this eventually; we should always find it, but for now alert if there’s a bug in our code
-      }
-
-      // 1. transform <style> tags
       styleTransforms.forEach((result, n) => {
         if (styleNodes[n].attributes) {
-          // 1b. Inject final CSS
+          // 1. Replace with final CSS
           const isHeadStyle = !styleNodes[n].content;
           if (isHeadStyle) {
             // Note: <style> tags in <head> have different attributes/rules, because of the parser. Unknown why
@@ -202,22 +184,22 @@ export default function ({ filename, fileID }: { filename: string; fileID: strin
             styleNodes[n].content.styles = result.css;
           }
 
-          // 3b. Update <style> attributes
+          // 2. Update <style> attributes
           const styleTypeIndex = styleNodes[n].attributes.findIndex(({ name }: any) => name === 'type');
+          // add type="text/css"
           if (styleTypeIndex !== -1) {
             styleNodes[n].attributes[styleTypeIndex].value[0].raw = 'text/css';
             styleNodes[n].attributes[styleTypeIndex].value[0].data = 'text/css';
           } else {
             styleNodes[n].attributes.push({ name: 'type', type: 'Attribute', value: [{ type: 'Text', raw: 'text/css', data: 'text/css' }] });
           }
+          // remove lang="*"
           const styleLangIndex = styleNodes[n].attributes.findIndex(({ name }: any) => name === 'lang');
           if (styleLangIndex !== -1) styleNodes[n].attributes.splice(styleLangIndex, 1);
+          // TODO: add data-astro for later
+          // styleNodes[n].attributes.push({ name: 'data-astro', type: 'Attribute', value: true });
         }
       });
-
-      // 2. inject finished <style> tags into root node
-      // TODO: pull out into <link> tags for deduping
-      rootNode.children = [...styleNodes, ...(rootNode.children || [])];
     },
   };
 }