From 79f8f149dcd3ac2bb671633c97f28c41f84d8490 Mon Sep 17 00:00:00 2001
From: ULIVZ <472590061@qq.com>
Date: Mon, 16 Apr 2018 13:07:32 -0500
Subject: [PATCH] feat: dropdown Items in Navbar (#13)

---
 README.md                           |   1 -
 docs/default-theme-config/README.md |  18 ++++
 docs/guide/README.md                |   1 -
 lib/default-theme/DropdownLink.vue  | 152 ++++++++++++++++++++++++++++
 lib/default-theme/NavLink.vue       |  34 +++++++
 lib/default-theme/NavLinks.vue      |  67 ++++++------
 lib/default-theme/Sidebar.vue       |   3 +-
 lib/default-theme/util.js           |  12 ++-
 8 files changed, 253 insertions(+), 35 deletions(-)
 create mode 100644 lib/default-theme/DropdownLink.vue
 create mode 100644 lib/default-theme/NavLink.vue

diff --git a/README.md b/README.md
index 1b7d2c5aaf..31c580ac95 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,6 @@ https://vuepress.vuejs.org/
 
 VuePress is still a work in progress. There are a few things that it currently does not support but are planned:
 
-- Dropdown Items in Navbar
 - Multi-Language Support
 - Algolia DocSearch Integration
 - Blogging support
diff --git a/docs/default-theme-config/README.md b/docs/default-theme-config/README.md
index 37a871d055..0d64c59ba9 100644
--- a/docs/default-theme-config/README.md
+++ b/docs/default-theme-config/README.md
@@ -50,6 +50,24 @@ module.exports = {
 }
 ```
 
+These links can also be dropdown menus if you provide nested items via `items`:
+
+```js
+module.exports = {
+  themeConfig: {
+    nav: [
+      {
+        text: 'Languages', 
+        items: [
+          { text: 'Chinese', link: '/language/chinese' },
+          { text: 'Japanese', link: '/language/japanese' }
+        ]
+      }
+    ]
+  }
+}
+```
+
 ## Sidebar
 
 To enable the sidebar, use `themeConfig.sidebar`. The basic configuration expects an Array of links:
diff --git a/docs/guide/README.md b/docs/guide/README.md
index 6c3cdeeccc..0761baa54a 100644
--- a/docs/guide/README.md
+++ b/docs/guide/README.md
@@ -30,7 +30,6 @@ Each markdown file is compiled into HTML with [markdown-it](https://github.com/m
 
 VuePress is still a work in progress. There are a few things that it currently does not support but are planned:
 
-- Dropdown Items in Navbar
 - Multi-Language Support
 - Algolia DocSearch Integration
 - Blogging support
diff --git a/lib/default-theme/DropdownLink.vue b/lib/default-theme/DropdownLink.vue
new file mode 100644
index 0000000000..cd3796ac66
--- /dev/null
+++ b/lib/default-theme/DropdownLink.vue
@@ -0,0 +1,152 @@
+<template>
+  <div class="dropdown-wrapper" :class="{ open }">
+    <div class="dropdown-title" @click="toggle">
+      <span class="title">{{ item.text }}</span>
+      <span class="arrow"></span>
+    </div>
+    <ul class="nav-dropdown">
+      <li
+        class="dropdown-item"
+        v-for="subItem in item.items"
+        :key="subItem.link">
+        <h4 v-if="subItem.type === 'links'">{{ subItem.text }}</h4>
+        <ul class="dropdown-subitem-wrapper" v-if="subItem.type === 'links'">
+          <li
+            class="dropdown-subitem"
+            v-for="childSubItem in subItem.items"
+            :key="childSubItem.link">
+            <nav-link :item="childSubItem"></nav-link>
+          </li>
+        </ul>
+        <nav-link v-else :item="subItem"></nav-link>
+      </li>
+    </ul>
+  </div>
+</template>
+
+<script>
+  import { isExternal, ensureExt } from './util'
+  import NavLink from './NavLink.vue'
+
+  export default {
+    components: { NavLink },
+    data() {
+      return {
+        open: false
+      }
+    },
+    props: {
+      item: {
+        required: true
+      }
+    },
+    methods: {
+      toggle() {
+        this.open = !this.open
+      }
+    }
+  }
+</script>
+
+<style lang="stylus">
+@import './styles/config.styl'
+
+.dropdown-wrapper
+  .dropdown-title
+    .arrow
+      display inline-block
+      vertical-align middle
+      margin-top -1px
+      margin-left 6px
+      width 0
+      height 0
+      border-left 4px solid transparent
+      border-right 4px solid transparent
+      border-top 5px solid #ccc
+  .nav-dropdown
+    .dropdown-item
+      color inherit
+      line-height 1.7rem
+      h4
+        margin 0.45rem 0 0
+        border-top 1px solid #eee
+        padding 0.45rem 1.5rem 0 1.25rem
+      .dropdown-subitem-wrapper
+        padding 0
+        list-style none
+        .dropdown-subitem
+          font-size 0.9em
+      a
+        display block
+        height 1.7rem
+        line-height 1.7rem
+        position relative
+        border-bottom none
+        font-weight 400
+        margin-bottom 0
+        padding 0 1.5rem 0 1.25rem
+        &:hover
+          color $accentColor
+        &.router-link-active
+          color $accentColor
+          &::after
+            content ""
+            width 0
+            height 0
+            border-left 5px solid $accentColor
+            border-top 4px solid transparent
+            border-bottom 4px solid transparent
+            position absolute
+            top calc(50% - 3px)
+            left 10px
+      &:first-child h4
+        margin-top 0
+        padding-top 0
+        border-top 0
+
+@media (max-width: $MQMobile)
+  .dropdown-wrapper
+    &.open .dropdown-title
+      margin-bottom 0.5rem
+    &:not(.open)
+      .dropdown-title .arrow
+        border-top 4px solid transparent
+        border-bottom 4px solid transparent
+        border-left 5px solid #ccc
+      .nav-dropdown
+        display none
+    .nav-dropdown
+      .dropdown-item
+        h4
+          border-top 0
+          margin-top 0
+          padding-top 0
+        h4, & > a
+          font-size 15px
+          height 2rem
+          line-height 2rem
+        .dropdown-subitem
+          font-size 14px
+          padding-left 1rem
+
+@media (min-width: $MQMobile)
+  .dropdown-wrapper
+    &:hover .nav-dropdown
+      display block
+    .nav-dropdown
+      display none
+      box-sizing border-box;
+      max-height calc(100vh - 2.7rem)
+      overflow-y auto
+      position absolute
+      top 100%
+      right 0
+      background-color #fff
+      padding 10px 0
+      border 1px solid #ddd
+      border-bottom-color #ccc
+      text-align left
+      border-radius 0.25rem
+      white-space nowrap
+      margin 0
+</style>
diff --git a/lib/default-theme/NavLink.vue b/lib/default-theme/NavLink.vue
new file mode 100644
index 0000000000..626fad52bc
--- /dev/null
+++ b/lib/default-theme/NavLink.vue
@@ -0,0 +1,34 @@
+<template>
+  <router-link
+    class="nav-link"
+    :to="link"
+    v-if="!isExternal(link)"
+    :exact="link === '/'"
+  >{{ item.text }}</router-link>
+  <a
+    v-else
+    :href="link"
+    target="_blank"
+    class="nav-link"
+    rel="noopener noreferrer"
+  >{{ item.text }}</a>
+</template>
+
+<script>
+  import { isExternal, ensureExt } from './util'
+  export default {
+    props: {
+      item: {
+        required: true
+      }
+    },
+    computed: {
+      link() {
+        return ensureExt(this.item.link)
+      }
+    },
+    methods: {
+      isExternal
+    }
+  }
+</script>
diff --git a/lib/default-theme/NavLinks.vue b/lib/default-theme/NavLinks.vue
index d3eab30659..b3bad047f7 100644
--- a/lib/default-theme/NavLinks.vue
+++ b/lib/default-theme/NavLinks.vue
@@ -1,21 +1,15 @@
 <template>
   <nav class="nav-links" v-if="userLinks.length || githubLink">
     <!-- user links -->
-    <template v-for="item in userLinks">
-      <a v-if="item.isOutbound"
-        :href="item.link"
-        target="_blank"
-        rel="noopener noreferrer">
-        {{ item.text }}
-      </a>
-      <router-link
-        v-else
-        :to="item.link"
-        :key="item.link"
-        :exact="item.link === '/'">
-        {{ item.text }}
-      </router-link>
-    </template>
+    <div
+      class="nav-item"
+      v-for="item in userLinks"
+      :key="item.link">
+      <dropdown-link
+        v-if="item.type === 'links'"
+        :item="item"></dropdown-link>
+      <nav-link v-else :item="item"></nav-link>
+    </div>
     <!-- github link -->
     <a v-if="githubLink"
       :href="githubLink"
@@ -30,16 +24,18 @@
 
 <script>
 import OutboundLink from './OutboundLink.vue'
-import { isActive, ensureExt, outboundRE } from './util'
+import { isActive, resolveNavLinkItem } from './util'
+import NavLink from './NavLink.vue'
+import DropdownLink from './DropdownLink.vue'
 
 export default {
-  components: { OutboundLink },
+  components: { OutboundLink, NavLink, DropdownLink },
   computed: {
     userLinks () {
-      return (this.$site.themeConfig.nav || []).map(item => ({
-        text: item.text,
-        link: ensureExt(item.link),
-        isOutbound: outboundRE.test(item.link)
+      return (this.$site.themeConfig.nav || []).map((link => {
+        return Object.assign(resolveNavLinkItem(link), {
+          items: (link.items || []).map(resolveNavLinkItem)
+        })
       }))
     },
     githubLink () {
@@ -63,21 +59,30 @@ export default {
 .nav-links
   display inline-block
   a
-    color inherit
-    font-weight 500
     line-height 1.25rem
-    margin-left 1.5rem
+    color inherit
     &:hover, &.router-link-active
       color $accentColor
+  .nav-item
+    cursor: pointer
+    position relative
+    display inline-block
+    margin-left 1.5rem
+    font-weight 500
+    line-height 2rem
+  .github-link
+    margin-left 1.5rem
 
 @media (max-width: $MQMobile)
-  .nav-links a
-    margin-left 0
+  .nav-links
+    .nav-item, .github-link
+      margin-left 0
 
 @media (min-width: $MQMobile)
-  .nav-links a
-    &:hover, &.router-link-active
-      color $textColor
-      margin-bottom -2px
-      border-bottom 2px solid lighten($accentColor, 5%)
+  .nav-links
+    a
+      &:hover, &.router-link-active
+        color $textColor
+        margin-bottom -2px
+        border-bottom 2px solid lighten($accentColor, 5%)
 </style>
diff --git a/lib/default-theme/Sidebar.vue b/lib/default-theme/Sidebar.vue
index d8c94c1fd5..c7be0cfa86 100644
--- a/lib/default-theme/Sidebar.vue
+++ b/lib/default-theme/Sidebar.vue
@@ -81,8 +81,9 @@ function resolveOpenGroupIndex (route, items) {
     display none
     border-bottom 1px solid $borderColor
     padding 0.5rem 0 0.75rem 0
-    a
+    .nav-item, .github-link
       display block
+      line-height 1.25rem
       font-weight 600
       font-size 1.1em
       padding 0.5rem 0 0.5rem 1.5rem
diff --git a/lib/default-theme/util.js b/lib/default-theme/util.js
index 1ac90661c1..f89ea8a3f1 100644
--- a/lib/default-theme/util.js
+++ b/lib/default-theme/util.js
@@ -16,8 +16,12 @@ export function getHash (path) {
   }
 }
 
+export function isExternal (path) {
+  return outboundRE.test(path)
+}
+
 export function ensureExt (path) {
-  if (outboundRE.test(path)) {
+  if (isExternal(path)) {
     return path
   }
   const hashMatch = path.match(hashRE)
@@ -147,6 +151,12 @@ export function groupHeaders (headers) {
   return headers.filter(h => h.level === 2)
 }
 
+export function resolveNavLinkItem (linkItem) {
+  return Object.assign(linkItem, {
+    type: linkItem.items && linkItem.items.length ? 'links' : 'link'
+  })
+}
+
 function resolveMatchingSidebarConfig (route, sidebarConfig) {
   if (Array.isArray(sidebarConfig)) {
     return {