I use this to automatically fix links in my react workshops. (This one's only for the testing-react-apps repo because those markdown files aren't rendered in a UI, the normal one is at https://gist.github.com/kentcdodds/436a77ff8977269e5fee39d9d89956de)

fix-feedback-links.js

#!/usr/bin/env node

const path = require('path')
const fs = require('fs')
const glob = require('glob')
const projectTitle = require(path.join(process.cwd(), 'package.json')).title

const linkRegex = /https?:\/\/ws\.kcd\.im.*?$/m

const titleRegex = {
  '.js': /^\/\/ (?<title>.*)$/,
  '.md': /^# (?<title>.*)$/,
}

// update feedback links
glob.sync('src/__tests__/**/*.md').forEach(filepath => {
  const {name: filename, ext} = path.parse(filepath)
  const fullFilepath = path.join(process.cwd(), filepath)
  const contents = fs.readFileSync(fullFilepath, {
    encoding: 'utf-8',
  })
  const firstLine = contents.split('\n')[0]
  const titleMatch = firstLine.match(titleRegex[ext])
  if (!titleMatch) {
    throw new Error(`Title is invalid for "${filepath}"`)
  }
  const title = titleMatch.groups.title.trim()
  const workshop = encodeURIComponent(projectTitle)
  const exercise = encodeURIComponent(`${filename}: ${title}`)
  const link = `https://ws.kcd.im/?ws=${workshop}&e=${exercise}&em=`
  if (contents.includes(link)) {
    return
  }
  if (linkRegex.test(contents)) {
    const newContents = contents.replace(linkRegex, link)
    fs.writeFileSync(fullFilepath, newContents)
  }
})

package.json

{
  "name": "fix-feedback-links",
  "version": "1.0.0",
  "description": "I use this to automatically fix feedback links in my workshops",
  "bin": "./fix-feedback-links.js",
  "dependencies": {
    "glob": "7.1.6"
  }
}