docs/.vuepress/theme/src/NavLinks.vue

<template>
  <nav
    class="nav-links"
    v-if="userLinks.length || repoLink"
  >
    <!-- user links -->
    <div
      class="nav-item"
      v-for="item in userLinks"
      :key="item.link"
    >
      <DropdownLink
        v-if="item.type === 'links'"
        :item="item"
      />
      <NavLink
        v-else
        :item="item"
      />
    </div>
  </nav>
</template>

<script>
import DropdownLink from './DropdownLink.vue'
import { resolveNavLinkItem } from './util'
import NavLink from './NavLink.vue'

export default {
  components: { NavLink, DropdownLink },

  computed: {
    userNav () {
      return this.$themeLocaleConfig.nav || this.$site.themeConfig.nav || []
    },

    nav () {
      const { locales } = this.$site
      if (locales && Object.keys(locales).length > 1) {
        const currentLink = this.$page.path
        const routes = this.$router.options.routes
        const themeLocales = this.$site.themeConfig.locales || {}
        const languageDropdown = {
          text: this.$themeLocaleConfig.selectText || 'Languages',
          items: Object.keys(locales).map(path => {
            const locale = locales[path]
            const text = themeLocales[path] && themeLocales[path].label || locale.lang
            let link
            // Stay on the current page
            if (locale.lang === this.$lang) {
              link = currentLink
            } else {
              // Try to stay on the same page
              link = currentLink.replace(this.$localeConfig.path, path)
              // fallback to homepage
              if (!routes.some(route => route.path === link)) {
                link = path
              }
            }
            return { text, link }
          })
        }
        return [...this.userNav, languageDropdown]
      }
      return this.userNav
    },

    userLinks () {
      return (this.nav || []).map(link => {
        return Object.assign(resolveNavLinkItem(link), {
          items: (link.items || []).map(resolveNavLinkItem)
        })
      })
    }
  }
}
</script>

<style lang="stylus">
@import './styles/config.styl'

.nav-links
  display inline-block
  a
    line-height 1.4rem
    color inherit
    &:hover, &.router-link-active
      color $accentColor
  .nav-item
    position relative
    display inline-block
    margin-left 2rem
    line-height 2rem

@media (max-width: $MQMobile)
  .nav-links
    .nav-item, .repo-link
      margin-left 0

@media (min-width: $MQMobile)
  .nav-links a
    &:hover, &.router-link-active
      color $textColor
  .nav-item > a:not(.external)
    &:hover, &.router-link-active
      color $accentColor
    &.router-link-active:after
      content ''
      display block
      width 100%
      height 3px
      position absolute
      bottom -0.77rem
      background-color $accentColor
</style>