documentation/.vuepress/theme/NavLink.vue

<template>
    <router-link
            class="nav-link"
            :to="link"
            v-if="!isExternal(link)"
            :exact="exact"
    >{{ item.text }}
    </router-link>
    <a
            v-else
            :href="link"
            class="nav-link external"
            :target="isMailto(link) || isTel(link) ? null : '_blank'"
            :rel="isMailto(link) || isTel(link) ? null : 'noopener noreferrer'"
    >
        {{ item.text }}
        <OutboundLink/>
    </a>
</template>

<script>
    import { isExternal, isMailto, isTel, ensureExt } from './util';

    export default {
        props: {
            item: {
                required: true
            }
        },
        computed: {
            link() {
                return ensureExt(this.item.link);
            },
            exact() {
                if (this.$site.locales) {
                    return Object.keys(this.$site.locales).some(rootLink => rootLink === this.link);
                }
                return this.link === '/';
            }
        },
        methods: {
            isExternal,
            isMailto,
            isTel
        }
    };
</script>