feat(website): linkify changelog version headers

strager · strager · commit 192e4197aab6 · 2023-01-18T22:48:42.000-08:00
diff --git a/website/public/releases/index.ejs.html b/website/public/releases/index.ejs.html
@@ -27,6 +27,22 @@
         padding-top: 2rem;
         margin-top: 2rem;
       }
+
+      h3 a,
+      h3 a:visited,
+      h3 a:link {
+        color: black;
+      }
+      h3 a:hover {
+        text-decoration: underline;
+      }
+      @media (prefers-color-scheme: dark) {
+        h3 a,
+        h3 a:visited,
+        h3 a:link {
+          color: white;
+        }
+      }
     </style>
   </head>
   <body class="side-bar-nav">
diff --git a/website/src/release-documentation.mjs b/website/src/release-documentation.mjs
@@ -2,6 +2,7 @@
 // See end of file for extended copyright information.
 
 import MarkdownIt from "markdown-it";
+import assert from "node:assert";
 
 let markdownParser = new MarkdownIt("commonmark");
 
@@ -10,6 +11,7 @@ export function releasesMarkdownToHTML(releasesMarkdown) {
   let tokens = markdownParser.parse(releasesMarkdown, env);
   tokens = removeTitle(tokens);
   tokens = demoteHeadings(tokens);
+  tokens = linkifyVersions(tokens);
 
   let html = markdownParser.renderer.render(
     tokens,
@@ -54,6 +56,81 @@ function demoteHeadings(markdownTokens) {
   });
 }
 
+function linkifyVersions(markdownTokens) {
+  markdownTokens = [...markdownTokens];
+
+  // @type Array<[number, number]>
+  let versionHeadingSpanIndexes = [];
+  for (let i = 0; i < markdownTokens.length; ++i) {
+    let token = markdownTokens[i];
+    if (token.tag === "h3") {
+      if (token.type === "heading_open") {
+        versionHeadingSpanIndexes.push([i]);
+      }
+      if (token.type === "heading_close") {
+        versionHeadingSpanIndexes[versionHeadingSpanIndexes.length - 1].push(i);
+      }
+    }
+  }
+
+  versionHeadingSpanIndexes.reverse();
+  for (let [headingBeginIndex, headingEndIndex] of versionHeadingSpanIndexes) {
+    let textTokens = markdownTokens.slice(
+      headingBeginIndex + 1,
+      headingEndIndex
+    );
+    let text = textTokens.map((token) => token.content).join("");
+    let versionInfo = extractVersionInfoFromHeadingText(text);
+    if (versionInfo === null) {
+      continue;
+    }
+    let currentVersionID = versionInfo.version;
+
+    let headingOpenToken = markdownTokens[headingBeginIndex];
+    let headingCloseToken = markdownTokens[headingEndIndex];
+    let newTokens = [
+      {
+        ...headingOpenToken,
+        attrs: [...(headingOpenToken.attrs ?? []), ["id", currentVersionID]],
+      },
+      {
+        type: "link_open",
+        tag: "a",
+        attrs: [["href", `#${currentVersionID}`]],
+      },
+      ...textTokens,
+      {
+        type: "link_close",
+        tag: "a",
+      },
+      headingCloseToken,
+    ];
+    markdownTokens.splice(
+      headingBeginIndex,
+      headingEndIndex - headingBeginIndex,
+      ...newTokens
+    );
+  }
+
+  return markdownTokens;
+}
+
+function extractVersionInfoFromHeadingText(text) {
+  let match = text.match(
+    /^(?<version>(?:\d+\.)*\d+) \((?<date>\d+-\d+-\d+)\)$/
+  );
+  if (match === null) {
+    if (text !== "Unreleased") {
+      console.warn(`warning: failed to parse version info from ${text}`);
+    }
+    return null;
+  }
+  return {
+    version: match.groups.version,
+    date: match.groups.date,
+  };
+}
+
 // quick-lint-js finds bugs in JavaScript programs.
 // Copyright (C) 2020  Matthew "strager" Glazar
 //
