replace yui autocomplete with plain javascript in sarch-box

The search box in the header is now implemented in plain javascript and
no longer using yui autocomplete.

Minor adjustments to the styling
- box-shadow is now the same as the one for dropdowns
- background of the suggestion list is the same as the background of the
  search input

core/src/main/resources/jenkins/views/JenkinsHeader/headerContent.jelly

@@ -34,7 +34,6 @@
                     </a>
 
                     <div id="search-box-completion" data-search-url="${searchURL}" />
-                    <st:adjunct includes="jenkins.views.JenkinsHeader.search-box" />
                 </div>
             </form>
         </div>

core/src/main/resources/jenkins/views/JenkinsHeader/search-box.js

@@ -1,6 +0,0 @@
-(function () {
-  var element = document.getElementById("search-box-completion");
-  if (element) {
-    createSearchBox(element.getAttribute("data-search-url"));
-  }
-})();

war/src/main/js/app.js

@@ -1,6 +1,7 @@
 import Dropdowns from "@/components/dropdowns";
 import Notifications from "@/components/notifications";
 import SearchBar from "@/components/search-bar";
+import SearchBox from "@/components/search-box";
 import Tooltips from "@/components/tooltips";
 import StopButtonLink from "@/components/stop-button-link";
 import ConfirmationLink from "@/components/confirmation-link";
@@ -9,6 +10,7 @@ import Dialogs from "@/components/dialogs";
 Dropdowns.init();
 Notifications.init();
 SearchBar.init();
+SearchBox.init();
 Tooltips.init();
 StopButtonLink.init();
 ConfirmationLink.init();

war/src/main/js/components/search-box/index.js

@@ -0,0 +1,202 @@
+import { getStyle } from "@/util/dom";
+
+function init() {
+  const input = document.getElementById("search-box");
+  const sizer = document.getElementById("search-box-sizer");
+  const comp = document.getElementById("search-box-completion");
+  if (!comp) {
+    return;
+  }
+
+  window.addEventListener("load", () => {
+    // copy font style of box to sizer
+    var ds = sizer.style;
+    ds.fontFamily = getStyle(input, "fontFamily");
+    ds.fontSize = getStyle(input, "fontSize");
+    ds.fontStyle = getStyle(input, "fontStyle");
+    ds.fontWeight = getStyle(input, "fontWeight");
+  });
+
+  const searchURL = comp.getAttribute("data-search-url");
+
+  const debounce = 300;
+  const maxResults = 25;
+  const highlightClass = "ac-highlight";
+  let req,
+    suggestions,
+    selected = -1,
+    visible = false,
+    currentValue;
+
+  comp.style.top = input.offsetHeight + 2 + "px";
+
+  input.autocomplete = "off";
+
+  ["input", "keydown", "blur", "focus"].forEach((ev) =>
+    input.addEventListener(ev, handleEvent),
+  );
+
+  const ul = document.createElement("ul");
+  ul.classList.add("jenkins-hidden");
+  comp.appendChild(ul);
+
+  const dataSrc = async (val) => {
+    let url = searchURL + "suggest?query=" + val;
+    const result = await fetch(url);
+    const data = await result.json();
+    const list = [];
+    data.suggestions.forEach((item, i) => {
+      if (i < maxResults) {
+        list.push(item.name);
+      }
+    });
+
+    return list;
+  };
+
+  function handleEvent(event) {
+    if (event.type === "focus") {
+      return;
+    }
+
+    if (event.type === "keydown" && handleKey(event)) {
+      return;
+    }
+
+    if (input.value === "") {
+      hide();
+      currentValue = null;
+      return;
+    }
+
+    if (event.type === "blur") {
+      hide();
+      return;
+    }
+
+    if (input.value === currentValue && visible) {
+      return;
+    }
+
+    currentValue = input.value;
+
+    clearTimeout(req);
+    req = setTimeout(search, debounce);
+  }
+
+  function handleKey(event) {
+    if (!visible) {
+      if (event.code === "Enter" && !input.value) {
+        event.preventDefault();
+      }
+      return ["Enter", "Escape", "Tab"].includes(event.code);
+    }
+
+    switch (event.code) {
+      case "ArrowUp":
+        return nav(-1, event);
+      case "ArrowDown":
+        return nav(1, event);
+      case "Tab":
+        if (selected >= 0) {
+          event.preventDefault();
+          select(selected);
+        }
+        hide();
+        return true;
+      case "Enter":
+        if (selected >= 0) {
+          event.preventDefault();
+          select(selected);
+        }
+        hide();
+        return true;
+      case "Escape":
+        hide();
+        return true;
+    }
+    return false;
+  }
+
+  async function search() {
+    if (!input.value) {
+      return;
+    }
+    suggestions = await dataSrc(input.value);
+    if (!suggestions.length) {
+      hide();
+      return;
+    }
+
+    showSuggestions();
+  }
+
+  function nav(direction, event) {
+    event.preventDefault();
+    const lastSelected = ul.querySelector(`.${highlightClass}`);
+    if (lastSelected) {
+      lastSelected.classList.remove(highlightClass);
+    }
+    selected = (selected + direction + suggestions.length) % suggestions.length;
+    ul.querySelector(`:nth-child(${selected + 1})`).classList.add(
+      highlightClass,
+    );
+    return true;
+  }
+
+  function select(i) {
+    input.value = currentValue = suggestions[i];
+  }
+
+  function showSuggestions() {
+    ul.innerHTML = "";
+    suggestions.forEach((item, i) => {
+      const li = document.createElement("li");
+      li.innerText = item;
+      if (i == selected) {
+        li.classList.add(highlightClass);
+      }
+      li.addEventListener("mousedown", () => select(i));
+      li.addEventListener("mouseover", () => {
+        ul.querySelectorAll("li").forEach((item) => {
+          item.classList.remove(highlightClass);
+        });
+        li.classList.add(highlightClass);
+        selected = i;
+      });
+      li.addEventListener("mouseout", () => {
+        li.classList.remove(highlightClass);
+      });
+      ul.appendChild(li);
+    });
+    ul.classList.remove("jenkins-hidden");
+    visible = true;
+  }
+
+  function hide() {
+    suggestions = [];
+    selected = -1;
+    if (visible) {
+      ul.classList.add("jenkins-hidden");
+      visible = false;
+      updatePos();
+    }
+  }
+
+  function updatePos() {
+    sizer.innerHTML = escapeHTML(input.value);
+    var cssWidth,
+      offsetWidth = sizer.offsetWidth;
+    if (offsetWidth > 0) {
+      cssWidth = offsetWidth + "px";
+    } else {
+      // sizer hidden on small screen, make sure resizing looks OK
+      cssWidth = getStyle(sizer, "minWidth");
+    }
+    input.style.width = comp.style.minWidth = "calc(85px + " + cssWidth + ")";
+  }
+
+  input.addEventListener("input", updatePos);
+}
+
+export default { init };

war/src/main/js/util/dom.js

@@ -10,3 +10,15 @@ export function toId(string) {
     .replace(/[\W_]+/g, "-")
     .toLowerCase();
 }
+
+export function getStyle(e, a) {
+  if (document.defaultView && document.defaultView.getComputedStyle) {
+    return document.defaultView
+      .getComputedStyle(e, null)
+      .getPropertyValue(a.replace(/([A-Z])/g, "-$1"));
+  }
+  if (e.currentStyle) {
+    return e.currentStyle[a];
+  }
+  return null;
+}

war/src/main/scss/components/_page-header.scss

@@ -167,16 +167,21 @@ a.page-header__brand-link {
 
 #search-box-completion {
   text-align: left;
-  width: 25em;
   position: absolute;
   z-index: 1000;
 }
 
 #search-box-completion ul {
   padding: 0.75rem 0;
+  min-width: 30em;
   width: 100%;
   margin: 0;
   list-style: none;
+  overflow: hidden;
+  background-color: var(--input-color);
+  box-shadow: var(--dropdown-box-shadow);
+  border: none;
+  border-radius: var(--form-input-border-radius);
 }
 
 #search-box-completion li {
@@ -186,6 +191,12 @@ a.page-header__brand-link {
   line-height: var(--line-height-base);
   overflow: hidden;
   text-overflow: ellipsis;
+  cursor: default;
+
+  &.ac-highlight {
+    background: var(--search-box-completion-bg);
+    font-weight: bold;
+  }
 }
 
 #search-box-sizer {