首先先調整 gatsby-node.js
在 gatsby-source-wordpress plugin 有建議寫法

以下是調整過的
gatsby-node.js

const _ = require(`lodash`)
const Promise = require(`bluebird`)
const path = require(`path`)
const slash = require(`slash`)

// Implement the Gatsby API “createPages”. This is
// called after the Gatsby bootstrap is finished so you have
// access to any information necessary to programmatically
// create pages.
// Will create pages for WordPress pages (route : /{slug})
// Will create pages for WordPress posts (route : /post/{slug})
exports.createPages = ({ graphql, actions }) => {
  const { createPage } = actions
  return new Promise((resolve, reject) => {
    // The “graphql” function allows us to run arbitrary
    // queries against the local WordPress graphql schema. Think of
    // it like the site has a built-in database constructed
    // from the fetched data that you can run queries against.

    // ==== PAGES (WORDPRESS NATIVE) ====
    graphql(
      `
        {
          allWordpressPage {
            edges {
              node {
                id
                slug
                status
                template
                title
                content
                template
              }
            }
          }
        }
      `
    )
      .then(result => {
        if (result.errors) {
          console.log(result.errors)
          reject(result.errors)
        }

        // Create Page pages.
        const pageTemplate = path.resolve("./src/templates/page.js")
        // We want to create a detailed page for each
        // page node. We'll just use the WordPress Slug for the slug.
        // The Page ID is prefixed with 'PAGE_'
        _.each(result.data.allWordpressPage.edges, edge => {
          // Gatsby uses Redux to manage its internal state.
          // Plugins and sites can use functions like "createPage"
          // to interact with Gatsby.

          createPage({
            // Each page is required to have a `path` as well
            // as a template component. The `context` is
            // optional but is often necessary so the template
            // can query data specific to each page.
            path: `/${edge.node.slug}/`,
            component: slash(pageTemplate),
            context: edge.node,
          })
        })
      })
      // ==== END PAGES ====

      // ==== POSTS (WORDPRESS NATIVE AND ACF) ====
      .then(() => {
        graphql(
          `
            {
              allWordpressPost {
                edges {
                  node {
                    id
                    title
                    slug
                    excerpt
                    content
                  }
                }
              }
            }
          `
        ).then(result => {
          if (result.errors) {
            console.log(result.errors)
            reject(result.errors)
          }
          const postTemplate = path.resolve("./src/templates/post.js")
          // We want to create a detailed page for each
          // post node. We'll just use the WordPress Slug for the slug.
          // The Post ID is prefixed with 'POST_'
          _.each(result.data.allWordpressPost.edges, edge => {
            createPage({
              path: `/post/${edge.node.slug}/`,
              component: slash(postTemplate),
              context: edge.node,
            })
          })
          resolve()
        })
      })
    // ==== END POSTS ====
  })
}

再把 pages folder 刪到剩 404.js，並新增一個名為 template 資料夾，裏頭有 page.js 和 post.js

新增檔案的內容皆為

import React from "react"

export default ({ pageContext }) => (
  <div>
    <h1>{pageContext.title}</h1>
    <div dangerouslySetInnerHTML={{ __html: pageContext.content }} />
  </div>
)

訪問 {{domain}}/sample-page

至於訪問根目錄會出現錯誤，跟我們404 page 還沒調整有關，明日再修改