factor out renderGemtextToHtml()

1 files changed, 72 insertions, 0 deletions

diff --git a/website/src/renderGemtextToHtml.ts b/website/src/renderGemtextToHtml.ts
new file mode 100644
index 0000000..f934f1e
--- /dev/null
+++ b/website/src/renderGemtextToHtml.ts
@@ -0,0 +1,72 @@
+import * as Gemtext from "gemtext";
+
+export function renderGemtextToHtml(gemtext: string, title: string): string {
+  return postProcessGemtextToHtml(
+    Gemtext.parse(gemtext.replace(`# ${title}`, "")).generate(
+      GemtextHTMLRenderer,
+    ),
+  );
+}
+
+const GemtextHTMLRenderer: Gemtext.Renderer<string> = {
+  preamble: function (): string {
+    return "";
+  },
+
+  postamble: function (): string {
+    return "";
+  },
+
+  text: function (content: string): string {
+    content = content.trim();
+    if (content === "") {
+      return "";
+    }
+    return `<p>${htmlEscape(content)}</p>`;
+  },
+
+  link: function (url: string, alt: string): string {
+    const imgExtensions: (string | undefined)[] = [
+      "webp",
+      "png",
+      "svg",
+      "gif",
+      "jpg",
+      "jpeg",
+      "apng",
+    ];
+    if (imgExtensions.includes(url.split(".").at(-1)?.toLowerCase())) {
+      return `<img src="${url}" alt="${alt}" />`;
+    }
+    return `<p>=> <a href="${url}">${alt}</a></p>`;
+  },
+
+  preformatted: function (content: string[], alt: string): string {
+    return `<pre alt="${alt}">${htmlEscape(content.join("\n"))}</pre>`;
+  },
+
+  heading: function (level: number, text: string): string {
+    return `<h${level}>${htmlEscape(text)}</h${level}>`;
+  },
+
+  unorderedList: function (content: string[]): string {
+    return `<ul>${content.map((li) => `<li>${htmlEscape(li)}</li>`).join("")}</ul>`;
+  },
+
+  quote: function (content: string): string {
+    return `<blockquote>${htmlEscape(content)}</blockquote>`;
+  },
+};
+
+function htmlEscape(str: string) {
+  return str.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
+}
+
+function postProcessGemtextToHtml(html: string): string {
+  html = mergeAdjacentBlockquotes(html);
+  return html;
+}
+
+function mergeAdjacentBlockquotes(html: string): string {
+  return html.replaceAll(/\<\/blockquote\>\<blockquote\>/gm, "<br>");
+}