feat: Improved the Native Search Algorithm

packages/@vuepress/plugin-search/SearchBox.vue

@@ -76,11 +76,43 @@ export default {
       const { pages } = this.$site
       const max = this.$site.themeConfig.searchMaxSuggestions || SEARCH_MAX_SUGGESTIONS
       const localePath = this.$localePath
-      const matches = item => (
-        item
-        && item.title
-        && item.title.toLowerCase().indexOf(query) > -1
-      )
+
+      const matchTest = (q, domain) => {
+        const escapeRegExp = (s) => {
+          return s.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&')
+        }
+
+        const words = q
+          .split(/\s+/g)
+          .map(s => s.trim())
+          .filter(s => !!s)
+        const hasTrailingSpace = q.endsWith(' ')
+        const searchRegex = new RegExp(
+          words
+            .map((word, i) => {
+              if (i + 1 === words.length && !hasTrailingSpace) {
+                // The last word - ok with the word being "startswith"-like
+                return `(?=.*\\b${escapeRegExp(word)})`
+              } else {
+                // Not the last word - expect the whole word exactly
+                return `(?=.*\\b${escapeRegExp(word)}\\b)`
+              }
+            })
+            .join('') + '.+',
+          'gi'
+        )
+        return searchRegex.test(domain)
+      }
+
+      const matches = (item, additionalStr = null) => {
+        let domain
+        domain = (item.title) ? item.title : ''
+        domain = (item.frontmatter && item.frontmatter.tags) ? domain + ' ' + item.frontmatter.tags.join(' ') : domain
+        if (additionalStr) domain = domain + ' ' + additionalStr
+
+        return matchTest(query, domain)
+      }
+
       const res = []
       for (let i = 0; i < pages.length; i++) {
         if (res.length >= max) break
@@ -101,7 +133,7 @@ export default {
           for (let j = 0; j < p.headers.length; j++) {
             if (res.length >= max) break
             const h = p.headers[j]
-            if (matches(h)) {
+            if (h.title && matches(p, h.title)) {
               res.push(Object.assign({}, p, {
                 path: p.path + '#' + h.slug,
                 header: h
@@ -227,7 +259,7 @@ export default {
     background #fff
     width 20rem
     position absolute
-    top 1.5rem
+    top 2 rem
     border 1px solid darken($borderColor, 10%)
     border-radius 6px
     padding 0.4rem

packages/docs/docs/theme/default-theme-config.md

@@ -357,10 +357,19 @@ search: false
 ```
 
 ::: tip
-Built-in Search only builds index from the title, `h2` and `h3` headers, if you need full text search, you can use [Algolia DocSearch](#algolia-docsearch).
+Built-in Search only builds index from the title, `h2` and `h3` headers and any tags added with `YAML front matter` as shown below, if you need full text search, you can use [Algolia Search](#algolia-search).
 :::
 
-### Algolia DocSearch
+```yaml
+---
+tags: 
+  - configuration
+  - theme
+  - indexing
+---
+```
+
+### Algolia Search
 
 The `themeConfig.algolia` option allows you to use [Algolia DocSearch](https://community.algolia.com/docsearch/) to replace the simple built-in search. To enable it, you need to provide at least `apiKey` and `indexName`: