build.js

const fs = require('fs')
const marked = require('marked')
const glob = require('glob')
const fm = require('front-matter')
const path = require('path')
const renderer = new marked.Renderer()

const fileNames = glob.sync(path.resolve('./contents/posts/*.md'))
const data = fileNames
  .map(fileName => {
    // Fileの中身を取得
    const contents = fs.readFileSync(fileName, 'utf8')
    // Front MatterでHeader部とBody部に分割
    const { attributes, body } = fm(contents)
    // BodyをMarkdown形式からHTMLに変換
    const parsedBody = marked(body, { renderer })
    return {
      ...attributes,
      body: parsedBody
    }
  })
fs.writeFileSync('./dist/posts.json', JSON.stringify(data, null, 2))