A script to migrate posts from Ghost's exported json to Gatsby

ghost-to-gatsby.js

const fs = require('fs');
const path = require('path');
const moment = require('moment');
const json = require('./8bitzen.ghost.2018-04-28.json');

const post_tags = json.db[0].data.posts_tags;
const tags = json.db[0].data.tags;

function ensureDirectoryExistence(filePath) {
  var dirname = path.dirname(filePath);
  if (fs.existsSync(dirname)) {
    return true;
  }
  ensureDirectoryExistence(dirname);
  fs.mkdirSync(dirname);
}

json.db[0].data.posts
  .filter(p => p.status === 'published')
  .forEach(({
    id,
    title,
    slug,
    published_at: published,
    mobiledoc
  }) => {
    const date = moment(published).format('YYYY-MM-DD');
    const markdown = JSON.parse(mobiledoc).cards[0][1].markdown;
    const associatedTags =
      '[' +
      post_tags
      .filter(t => t.post_id === id)
      .map(t => {
        const associatedTag = tags.find(tag => tag.id === t.tag_id);
        return `"${associatedTag.name}"`;
      })
      .reduce(
        (accumulator, currentValue) => `${currentValue},${accumulator}`
      ) +
      ']';

    const content = `---
title: "${title.replace (/\:\n/)}"
date: "${date}"
tags: ${associatedTags}
author: John Smith
publish: true
---
${markdown}
            `;
    const dir = path.join(__dirname, `/pages/${date}-${slug}`);
    if (!fs.existsSync(dir)) {
      fs.mkdirSync(dir);
    }

    fs.writeFileSync(
      path.join(__dirname, `/pages/${date}-${slug}/index.md`),
      content
    );
  });