/**

* Generates changelog Markdown for pinned npm packages in a package.json diff

*

* Usage: git diff package.json | node package-changelog.js

*/

let fs = require('fs')

let changes = fs.readFileSync(0, 'utf-8')

let re = /^(?<change>[+-])\s*"(?<pkg>[^"]+)"\s*:\s*"(?<version>\d+\.\d+\.\d+)"/gm

let deps = new Map()

Array.from(changes.matchAll(re)).forEach(({groups}) => {

if (!deps.has(groups.pkg)) {

deps.set(groups.pkg, {})

}

deps.get(groups.pkg)[groups.change] = groups.version

})

let changelog = Array.from(deps.keys())

.sort()

.map((pkg) => {

let versions = deps.get(pkg)

if (!versions.hasOwnProperty('-')) {

return `- ${pkg}: v${versions['+']}`

}

return `- ${pkg}: v${versions['-']} → [v${versions['+']}]()`

})

.join('\n')

console.log(changelog)