restore the previously chosen result

src/client/search.js

@@ -38,20 +38,27 @@ input.addEventListener("input", () => {
   container.setAttribute("data-shortcut", ""); // prevent conflict with close button
   sidebar.classList.add("observablehq-search-results"); // hide pages while showing search results
   const results = index.search(currentValue, {boost: {title: 4, keywords: 4}, fuzzy: 0.15, prefix: true});
+  const previous = sessionStorage.getItem("observablehq-search-chosen");
   resultsContainer.innerHTML =
     results.length === 0
       ? "<div>no results</div>"
       : `<div>${results.length.toLocaleString("en-US")} result${results.length === 1 ? "" : "s"}</div><ol>${results
-          .map(renderResult)
+          .map(({id, score, title}, i) => {
+            const href = import.meta.resolve(`../${id}`);
+            return `<li data-score="${Math.min(5, Math.round(0.6 * score))}" class="observablehq-link${
+              (previous === null ? i === 0 : href === previous) ? ` ${activeClass}` : ""
+            }"><a href="${escapeDoubleQuote(
+              href
+            )}" onclick='sessionStorage.setItem("observablehq-search-chosen",this.getAttribute("href"))'
+            >${escapeText(String(title ?? "—"))}</a></li>`;
+          })
           .join("")}</ol>`;
+  if (previous !== null) {
+    resultsContainer.querySelector(`.${activeClass}`).scrollIntoView({block: "nearest"});
+    sessionStorage.removeItem("observablehq-search-chosen");
+  }
 });
 
-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(String(title ?? "—"))}</a></li>`;
-}
-
 function escapeDoubleQuote(text) {
   return text.replace(/["&]/g, entity);
 }