package-lock-diff.js

/**
 *  This file can be used to reformat the output of https://www.npmjs.com/package/diff-package-lock
 *  so that the diff can be displayed with diff syntax highlighting in a GitHub
 *  PR.
 *
 *  How do I use this?
 *  1. Download this script to your local machine
 *  2. Run `npx diff-package-lock main`
 *  3. Copy and paste the output into a new file: package-diff.txt (required as
 *     diff-package-lock doesn't let us disable colorization of its output).
 *  3. Run this script passing the file created in step 3 as the first
 *     argument and direct the output to `pbcopy`:
 *     `node ./package-lock-diff.js package-diff.txt | pbcopy`
 *  4. In your GitHub PR, add a diff code block and paste the result:
 *     ```diff
 *     <paste>
 *     ```
 *  5. Preview your PR description - the diff should show added packages in green and removed
 *     packages in red. Packages which have had a version change show in the default text colour.
 */
const fs = require('fs')

const ADDED_PATTERN = / \+ /
const REMOVED_PATTERN = / - /
const CHANGED_PATTERN = / -> /

const filename = process.argv[2]
const dest = process.argv[3]

const lines = fs.readFileSync(filename, 'utf-8').split('\n')

const newLines = []

lines.forEach((line) => {
  if (ADDED_PATTERN.test(line)) {
    newLines.push(`+ ${line}`)
  } else if (REMOVED_PATTERN.test(line)) {
    newLines.push(`- ${line}`)
  } else if (CHANGED_PATTERN.test(line)) {
    newLines.push(`  ${line}`)
  }
})

newLines.forEach((line) => {
  console.log(line)
})

if (dest) {
  fs.writeFileSync(dest, newLines.join('\n'))
}