From 9bfd6b12fe0359e6a6591cb987f95d6a36bd656d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Rivi=C3=A8re?= <fil@rezo.net>
Date: Wed, 21 Aug 2024 14:12:59 +0200
Subject: [PATCH] boolean private option to skip the default font links

---
 docs/config.md         |  4 ----
 observablehq.config.ts |  7 +++----
 src/config.ts          | 29 +++++++++++++++++------------
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/docs/config.md b/docs/config.md
index 47797f058..fa4d8624b 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -300,7 +300,3 @@ The set of replacements for straight double and single quotes used when the [**t
 ## linkify <a href="https://github.com/observablehq/framework/releases/tag/v1.7.0" class="observablehq-version-badge" data-version="^1.7.0" title="Added in 1.7.0"></a>
 
 If true (the default), automatically convert URL-like text to links in Markdown.
-
-## extraHead <a href="https://github.com/observablehq/framework/pull/1588" class="observablehq-version-badge" data-version="prerelease" title="Added in #1588"></a>
-
-An HTML fragment to add at the beginning of the [head](#head). Defaults to the links necessary to use the Source Serif Pro font from Google Fonts (see [#423](https://github.com/observablehq/framework/issues/423)).
diff --git a/observablehq.config.ts b/observablehq.config.ts
index 1fd987a7a..53efc56f4 100644
--- a/observablehq.config.ts
+++ b/observablehq.config.ts
@@ -15,9 +15,6 @@ export default {
   root: "docs",
   output: "docs/.observablehq/dist",
   title: "Observable Framework",
-  extraHead: `<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
-<link rel="preload" as="style" href="https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&family=Spline+Sans+Mono:ital,wght@0,300..700;1,300..700&display=swap" crossorigin>
-<link rel="stylesheet" type="text/css" href="https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&family=Spline+Sans+Mono:ital,wght@0,300..700;1,300..700&display=swap" crossorigin>`,
   pages: [
     {name: "What is Framework?", path: "/what-is-framework"},
     {name: "Getting started", path: "/getting-started"},
@@ -89,7 +86,8 @@ export default {
     {name: "Contributing", path: "/contributing", pager: false}
   ],
   base: "/framework",
-  head: `<link rel="preload" as="style" href="https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&family=Spline+Sans+Mono:ital,wght@0,300..700;1,300..700&display=swap" crossorigin>
+  head: `<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+<link rel="preload" as="style" href="https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&family=Spline+Sans+Mono:ital,wght@0,300..700;1,300..700&display=swap" crossorigin>
 <link rel="stylesheet" type="text/css" href="https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&family=Spline+Sans+Mono:ital,wght@0,300..700;1,300..700&display=swap" crossorigin>
 <link rel="apple-touch-icon" href="/observable.png">
 <link rel="icon" type="image/png" href="/observable.png" sizes="32x32">${
@@ -100,6 +98,7 @@ export default {
       : ""
   }
 <script type="module">/Win/.test(navigator.platform) || Array.from(document.querySelectorAll(".win"), (e) => e.remove())</script>`,
+  _ignoreDefaultFontLinks: true,
   header: `<div style="display: flex; align-items: center; gap: 0.5rem; height: 2.2rem; margin: -1.5rem -2rem 2rem -2rem; padding: 0.5rem 2rem; border-bottom: solid 1px var(--theme-foreground-faintest); font: 500 16px var(--sans-serif);">
   <a href="https://observablehq.com/" target="_self" rel="" style="display: flex; align-items: center;">
     <svg width="22" height="22" viewBox="0 0 21.92930030822754 22.68549919128418" fill="currentColor">
diff --git a/src/config.ts b/src/config.ts
index ed35de1bc..3bbb65fd6 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -105,7 +105,6 @@ export interface ConfigSpec {
   head?: unknown;
   header?: unknown;
   footer?: unknown;
-  extraHead?: unknown;
   interpreters?: unknown;
   title?: unknown;
   pages?: unknown;
@@ -116,6 +115,7 @@ export interface ConfigSpec {
   quotes?: unknown;
   cleanUrls?: unknown;
   markdownIt?: unknown;
+  _ignoreDefaultFontLinks?: unknown;
 }
 
 interface ScriptSpec {
@@ -238,7 +238,7 @@ export function normalizeConfig(spec: ConfigSpec = {}, defaultRoot?: string, wat
   const sidebar = spec.sidebar === undefined ? undefined : Boolean(spec.sidebar);
   const scripts = spec.scripts === undefined ? [] : normalizeScripts(spec.scripts);
   const head = combine(
-    pageFragment(spec.extraHead === undefined ? defaultExtraHead() : spec.extraHead),
+    spec._ignoreDefaultFontLinks ? null : defaultFontHeaders(),
     pageFragment(spec.head === undefined ? "" : spec.head)
   );
   const header = pageFragment(spec.header === undefined ? "" : spec.header);
@@ -293,7 +293,7 @@ function defaultFooter(): string {
   )}">${formatLocaleDate(date)}</a>.`;
 }
 
-function defaultExtraHead(): string {
+function defaultFontHeaders(): string {
   const href =
     "https://fonts.googleapis.com/css2?family=Source+Serif+Pro:ital,wght@0,400;0,600;0,700;1,400;1,600;1,700&amp;display=swap";
   return `<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
@@ -430,13 +430,18 @@ export function stringOrNull(spec: unknown): string | null {
   return spec == null || spec === false ? null : String(spec);
 }
 
-function combine(...parts: (PageFragmentFunction | string | null)[]): PageFragmentFunction | string | null {
-  parts = parts.filter((d) => d);
-  return parts.length > 1
-    ? function ({title, data, path}) {
-        return Array.from(parts, (f) => (typeof f === "function" ? f({title, data, path}) : f))
-          .filter((d) => d != null)
-          .join("\n");
-      }
-    : parts[0] ?? null;
+function combine(
+  links: string | null,
+  head: PageFragmentFunction | string | null
+): PageFragmentFunction | string | null {
+  return links
+    ? typeof head === "function"
+      ? (d) => {
+          const h = head(d);
+          return h ? `${links}\n${h}` : links;
+        }
+      : head
+      ? `${links}\n${head}`
+      : links
+    : head;
 }