Start work on search feature with lunr

assets/book.scss

@@ -137,6 +137,23 @@ ul.pagination {
   display: none;
 }
 
+.book-search {
+  border: 0;
+  border-bottom: $padding-1 solid $gray-200;
+  outline: none;
+  // padding: $padding-4 $padding-8 $padding-4 $padding-16+$padding-4;
+  padding: $padding-4 $padding-8 $padding-4 0;
+  margin-bottom: $padding-4;
+  width: 100%;
+
+  // background: url("svg/search.svg") left center no-repeat;
+  // background-size: $padding-16;
+
+  &:focus {
+    border-bottom-color: $body-font-color;
+  }
+}
+
 .book-toc {
   flex: 0 0 $toc-width;
   font-size: $font-size-12;
@@ -211,6 +228,7 @@ aside nav,
 @media screen and (max-width: $sm-breakpoint) {
   .book-menu {
     margin-left: -$menu-width;
+    font-size: $font-size-base;
   }
 
   .book-header {

assets/search.js

@@ -0,0 +1,41 @@
+addEventListener("load", function() {
+  let input = document.querySelector("#book-search");
+  let results = document.querySelector("#book-search-results");
+
+  Promise.all([
+    loadScript("{{ "lunr.min.js" | relURL }}"),
+    loadScript("{{ "index.json" | relURL }}")
+  ]).then(enableLunr);
+
+  function enableLunr() {
+    results.idx = lunr(function() { 
+      this.ref('href')
+      this.field('title')
+      this.field('content')
+
+      window.lunrData.forEach(function (page) {
+        this.add(page)
+      }, this)
+    });
+    input.addEventListener("keyup", search);
+  }
+
+  function search() {
+    if (input.value) {
+      var hits = results.idx.search(`${input.value}*`);
+      results.innerHTML = JSON.stringify(hits);
+    } else {
+      results.innerHTML = '';
+    }
+  }
+
+  function loadScript(src) {
+    return new Promise(function(resolve, reject) {
+      let script = document.createElement('script');
+      script.src = src;
+      script.onload = () => resolve(script);
+  
+      document.head.append(script);
+    });
+  }
+});