update-readme.js

#!/usr/bin/env node

// [start-readme]
//
// This script crawls the script directory, hooks on special comment markers
// in each script, and adds the comment to `script/README.md`.
//
// [end-readme]

import { fileURLToPath } from 'url'
import path from 'path'
import fs from 'fs/promises'
import walk from 'walk-sync'
import dedent from 'dedent'
import { difference } from 'lodash-es'

const __dirname = path.dirname(fileURLToPath(import.meta.url))

const readme = path.join(__dirname, 'README.md')

const startComment = 'start-readme'
const endComment = 'end-readme'
const startCommentRegex = new RegExp(startComment)
const endCommentRegex = new RegExp(endComment)

const ignoreList = ['README.md']

const scriptsToRuleThemAll = ['bootstrap', 'server', 'test']

const allScripts = walk(__dirname, { directories: false }).filter((script) =>
  ignoreList.every((ignoredPath) => !script.includes(ignoredPath)),
)

const otherScripts = difference(allScripts, scriptsToRuleThemAll)

// build an object with script name as key and readme comment as value
const allComments = {}
for (const script of allScripts) {
  const fullPath = path.join(__dirname, script)

  let addToReadme = false
  const readmeComment = (await fs.readFile(fullPath, 'utf8'))
    .split('\n')
    .filter((cmt) => {
      if (startCommentRegex.test(cmt)) addToReadme = true
      if (endCommentRegex.test(cmt)) addToReadme = false
      if (addToReadme && !cmt.includes(startComment) && !cmt.includes(endComment)) return cmt
      return false
    })
    // remove comment markers and clean up newlines
    .map((cmt) => cmt.replace(/^(\/\/|#) ?/m, ''))
    .join('\n')
    .trim()

  allComments[script] = readmeComment
    // preserve double newlines as multiline list items
    .replace(/\n\n/g, '\n\n\n    ')
    // remove single newlines
    .replace(/\n(?!\n)/g, ' ')
}

// turn the script names/comments into itemized lists in the README
const template = `# Scripts

## Scripts to rule them all

This directory follows the [Scripts to Rule Them All](https://githubengineering.com/scripts-to-rule-them-all/) pattern:

${createTemplate(scriptsToRuleThemAll)}

## Additional scripts

${createTemplate(otherScripts)}
`

// update the readme
if (template === (await fs.readFile(readme, 'utf8'))) {
  console.log('The README is up-to-date!')
} else {
  await fs.writeFile(readme, template)
  console.log('The README.md has been updated!')
}

function createTemplate(arrayOfScripts) {
  return arrayOfScripts
    .map((script) => {
      const comment = allComments[script]
      return dedent`### [\`${script}\`](${script})\n\n${comment}\n\n---\n\n`
    })
    .join('\n')
}