From 1f93499ecef7ab5e1d137448f199402fd9bc9949 Mon Sep 17 00:00:00 2001
From: saicaca <zephyird@gmail.com>
Date: Sat, 3 Aug 2024 16:03:03 +0800
Subject: [PATCH] feat: use the first paragraph as the excerpt if `description`
 is not set

---
 astro.config.mjs              |  3 ++-
 src/components/PostCard.astro |  4 ++--
 src/plugins/remark-excerpt.js | 16 ++++++++++++++++
 3 files changed, 20 insertions(+), 3 deletions(-)
 create mode 100644 src/plugins/remark-excerpt.js

diff --git a/astro.config.mjs b/astro.config.mjs
index b732012..877ca42 100644
--- a/astro.config.mjs
+++ b/astro.config.mjs
@@ -17,6 +17,7 @@ import { AdmonitionComponent } from "./src/plugins/rehype-component-admonition.m
 import { GithubCardComponent } from "./src/plugins/rehype-component-github-card.mjs"
 import {parseDirectiveNode} from "./src/plugins/remark-directive-rehype.js";
 import { remarkReadingTime } from "./src/plugins/remark-reading-time.mjs"
+import {remarkExcerpt} from "./src/plugins/remark-excerpt.js";
 
 const oklchToHex = (str) => {
   const DEFAULT_HUE = 250
@@ -68,7 +69,7 @@ export default defineConfig({
     }),
   ],
   markdown: {
-    remarkPlugins: [remarkMath, remarkReadingTime, remarkGithubAdmonitionsToDirectives, remarkDirective, parseDirectiveNode],
+    remarkPlugins: [remarkMath, remarkReadingTime, remarkExcerpt, remarkGithubAdmonitionsToDirectives, remarkDirective, parseDirectiveNode],
     rehypePlugins: [
       rehypeKatex,
       rehypeSlug,
diff --git a/src/components/PostCard.astro b/src/components/PostCard.astro
index 14002a7..1c7e37b 100644
--- a/src/components/PostCard.astro
+++ b/src/components/PostCard.astro
@@ -48,8 +48,8 @@ const { remarkPluginFrontmatter } = await entry.render();
         <PostMetadata published={published} tags={tags} category={category} hideTagsForMobile={true} class="mb-4"></PostMetadata>
 
         <!-- description -->
-        <div class="transition text-75 mb-3.5 pr-4">
-            { description }
+        <div class:list={["transition text-75 mb-3.5 pr-4", {"line-clamp-2 md:line-clamp-1": !description}]}>
+            { description || remarkPluginFrontmatter.excerpt }
         </div>
 
         <!-- word count and read time  -->
diff --git a/src/plugins/remark-excerpt.js b/src/plugins/remark-excerpt.js
new file mode 100644
index 0000000..3fc8315
--- /dev/null
+++ b/src/plugins/remark-excerpt.js
@@ -0,0 +1,16 @@
+import { toString } from 'mdast-util-to-string'
+
+/* Use the post's first paragraph as the excerpt */
+export function remarkExcerpt() {
+    return (tree, { data }) => {
+        let excerpt = '';
+        for (let node of tree.children) {
+            if (node.type !== 'paragraph') {
+                continue
+            }
+            excerpt = toString(node)
+            break
+        }
+        data.astro.frontmatter.excerpt = excerpt
+    };
+}
\ No newline at end of file