Base.js

import HEML, { createMetaElement } from '@heml/utils' // eslint-disable-line no-unused-vars
import Meta from './Meta'
import isAbsoluteUrl from 'is-absolute-url'
import { resolve } from 'url'
import { has, first } from 'lodash'

export default createMetaElement('base', {
  parent: [ 'head' ],
  children: false,
  unique: true,
  defaultAttrs: { href: '' },

  render (attrs, contents) {
    Meta.set('base', attrs.href)

    return false
  },

  preRender ({ $ }) {
    const base = first($.findNodes('base'))

    if (base) {
      const baseUrl = base.attr('href')

      $('[href], [src]')
        .each((i, node) => {
          const attr = has(node.attribs, 'href') ? 'href' : 'src'

          if (has(node.attribs, attr) && !isAbsoluteUrl(node.attribs[attr])) {
            node.attribs[attr] = resolve(baseUrl, node.attribs[attr])
          }
        })
    }
  }
})