bug fixes for search (#826)

* add the home page to the default list of indexable pages
- even though it's not in pages, it's not ‘unlisted’
- one can still opt out with index: false, as we do for this documentation

* when the page title is undefined, replace with an emdash (avoids a crash when indexing untitled pages)

* type safety (for title = a number)

Author: Fil

src/client/search.js

@@ -43,7 +43,7 @@ input.addEventListener("input", () => {
 function renderResult({id, score, title}, i) {
   return `<li data-score="${Math.min(5, Math.round(0.6 * score))}" class="observablehq-link${
     i === 0 ? ` ${activeClass}` : ""
-  }"><a href="${escapeDoubleQuote(import.meta.resolve(`../${id}`))}">${escapeText(title)}</a></li>`;
+  }"><a href="${escapeDoubleQuote(import.meta.resolve(`../${id}`))}">${escapeText(String(title ?? "—"))}</a></li>`;
 }
 
 function escapeDoubleQuote(text) {

src/search.ts

@@ -30,7 +30,7 @@ export async function searchIndex(config: Config, effects = defaultEffects): Pro
   if (indexCache.has(config) && indexCache.get(config).freshUntil > +new Date()) return indexCache.get(config).json;
 
   // Get all the listed pages (which are indexed by default)
-  const pagePaths = new Set();
+  const pagePaths = new Set(["/index"]);
   for (const p of pages) {
     if ("path" in p) pagePaths.add(p.path);
     else for (const {path} of p.pages) pagePaths.add(path);