gridsome.server.js

// Server API makes it possible to hook into various parts of Gridsome
// on server-side and add custom data to the GraphQL data layer.
// Learn more: https://gridsome.org/docs/server-api

// Changes here require a server restart.
// To restart press CTRL + C in terminal and run `gridsome develop`

const fs = require("fs")
const path = require("path")
const { pathPrefix } = require("./gridsome.config")

module.exports = function(api, options) {
  api.loadSource(store => {
    /*
    Clean the pathPrefix
    ====================
    not used =>  '/'
    ''       =>  '/'
    '/'      =>  '/'
    '/path'  =>  '/path'
    'path'   =>  '/path'
    'path/'  =>  '/path'
    '/path/' =>  '/path'
    */
    const cleanedPathPrefix = `${
      pathPrefix
        ? ["", ...pathPrefix.split("/").filter(dir => dir.length)].join("/")
        : ""
    }`

    /*
    Query
    =====
    <static-query>        <!-- or a page-query -->
    {
      metaData{
        pathPrefix
      }
    }
    </static-query>

    Requests for static files should look like this:
    ===============================================
    Using static-queries: axios( this.$static.metaData.pathPrefix + "/fileName" )
    Using page-queries,   axios( this.$page.metaData.pathPrefix   + "/fileName" )
    */
    store.addMetadata("pathPrefix", cleanedPathPrefix)
  })
}