[398] document is not defined

I'm trying to include vue2-dragula, I've setup in plugins vue2-dragula.js with:

import Vue from 'vue'
import { Vue2Dragula } from 'vue2-dragula'

if (process.BROWSER_BUILD) {
  Vue.use(Vue2Dragula, {
    logging: {
      service: true
    }
  })
}

Then included in nuxt.config plugins: ['~plugins/vue2-dragula']

It seems that process.BROWSER_BUILD isn't being factored in?