I use this to automatically fix links in my react workshops

fix-links.js

#!/usr/bin/env node

const path = require('path')
const fs = require('fs')
const glob = require('glob')
const pkg = require(path.join(process.cwd(), 'package.json'))
const {title: projectTitle, homepage: projectHomepage} = pkg

// update production deploy links
glob.sync('src/**/*.md').forEach(filepath => {
  const parsed = path.parse(filepath)
  const {name} = parsed
  let exerciseExt
  const exerciseHtmlPath = path.format({...parsed, base: `${name}.html`})
  const exerciseJsPath = path.format({...parsed, base: `${name}.js`})
  const exerciseTsPath = path.format({...parsed, base: `${name}.ts`})
  const exerciseTsxPath = path.format({...parsed, base: `${name}.tsx`})
  if (fs.existsSync(exerciseHtmlPath)) {
    exerciseExt = '.html'
  } else if (fs.existsSync(exerciseJsPath)) {
    exerciseExt = '.js'
  } else if (fs.existsSync(exerciseTsPath)) {
    exerciseExt = '.ts'
  } else if (fs.existsSync(exerciseTsxPath)) {
    exerciseExt = '.tsx'
  } else {
    throw new Error(`Unsupported exercise type for "${name}"`)
  }
  const fullFilepath = path.join(process.cwd(), filepath)
  const contents = fs.readFileSync(fullFilepath, {
    encoding: 'utf-8',
  })
  const lines = contents.split('\n')

  const exerciseProdDeployLines = `
Production deploys:

- [Exercise](${projectHomepage}isolated/exercise/${name}${exerciseExt})
- [Final](${projectHomepage}isolated/final/${name}${exerciseExt})
  `
    .trim()
    .split('\n')

  const getExtraDeployLines = extraNumber => [
    `[Production deploy](${projectHomepage}isolated/final/${name}.extra-${extraNumber}${exerciseExt})`,
  ]

  const newLines = []
  for (let lineIndex = 0; lineIndex < lines.length; lineIndex++) {
    const line = lines[lineIndex]
    newLines.push(line)

    const extraCreditMatch = line.match(/### (?<number>\d+)\. 💯 /)

    if (/## Exercise$/.test(line)) {
      newLines.push('', ...exerciseProdDeployLines)
      if (lines[lineIndex + 2].startsWith('Production deploys:')) {
        // already existed, skip indexes
        lineIndex = lineIndex + exerciseProdDeployLines.length + 1
      }
    } else if (extraCreditMatch) {
      const number = extraCreditMatch.groups.number
      const extraDeployLines = getExtraDeployLines(number)
      newLines.push('', ...extraDeployLines)
      if (lines[lineIndex + 2].startsWith('[Production deploy]')) {
        // already existed, skip indexes
        lineIndex = lineIndex + extraDeployLines.length + 1
      }
    }
  }

  fs.writeFileSync(fullFilepath, newLines.join('\n'))
})

// update notes
glob.sync('src/**/*.md').forEach(filepath => {
  const fullFilepath = path.join(process.cwd(), filepath)
  const contents = fs.readFileSync(fullFilepath, {
    encoding: 'utf-8',
  })
  const notesText = `
## 📝 Your Notes

Elaborate on your learnings here in \`${filepath}\`
  `.trim()
  if (contents.includes(notesText)) return

  const lines = contents.split('\n')
  const notesLines = notesText.trim().split('\n')
  notesLines.push('') // add a newline

  const notesLineIndex = lines.findIndex(line => line === '## 📝 Your Notes')
  const replaceLines = notesLineIndex !== -1
  lines.splice(2, replaceLines ? notesLines.length : 0, ...notesLines)
  fs.writeFileSync(fullFilepath, lines.join('\n'))
})

// update feedback links
glob.sync('src/**/*.md').forEach(filepath => {
  const {name: filename} = 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(/# (?<title>.*)$/)
  if (!titleMatch) {
    throw new Error(`Title is invalid for "${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
  }

  const feedbackLinkRegex = /\(https?:\/\/ws\.kcd\.im.*?\)/

  if (!feedbackLinkRegex.test(contents)) {
    throw new Error(`Exercise "${filepath}" is missing workshop feedback link`)
  }
  const newContents = contents.replace(feedbackLinkRegex, link)
  fs.writeFileSync(fullFilepath, newContents)
})

// update links to isolated examples
glob
  .sync('src/+(examples|final|exercise)/**/*.+(js|html|ts|tsx)', {
    ignore: ['**/__tests__/**', '**/*.test.*/**'],
  })
  .forEach(filepath => {
    const {ext} = path.parse(filepath)
    const fullFilepath = path.join(process.cwd(), filepath)
    const contents = fs.readFileSync(fullFilepath, {
      encoding: 'utf-8',
    })

    const linkBase = 'http://localhost:3000/isolated'
    const isHtml = ext === '.html'
    const link = `${linkBase}${filepath.replace(/^src/, '')}`
    const linkLine = isHtml ? `<!-- ${link} -->` : `// ${link}`
    const commentStart = isHtml ? '<!--' : '//'

    const lines = contents
      .split('\n')
      // filter out any existing link line (might be old)
      .filter(line => !line.trim().startsWith(`${commentStart} ${linkBase}`))

    const linkLineIndex = lines.findIndex(
      line => !line.trim().startsWith(commentStart),
    )
    lines.splice(linkLineIndex, 0, linkLine)

    // add empty line after the link if there isn't one already
    if (lines[linkLineIndex + 1].trim() !== '') {
      lines.splice(linkLineIndex + 1, 0, '')
    }
    const newContents = lines.join('\n')
    fs.writeFileSync(fullFilepath, newContents)
  })

package.json

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