Add release hook to format the changelog by labels

package.json

@@ -29,7 +29,7 @@
     "types": "lerna run types --stream",
     "typescript": "lerna run typescript",
     "prepublish": "lerna run prepublish",
-    "publish-canary": "lerna version prerelease --preid canary --force-publish && release --pre",
+    "publish-canary": "lerna version prerelease --preid canary --force-publish && release --pre --skip-questions",
     "publish-stable": "lerna version --force-publish",
     "lint-staged": "lint-staged",
     "next": "node packages/next/dist/bin/next",
@@ -109,7 +109,7 @@
     "react": "16.12.0",
     "react-dom": "16.12.0",
     "react-ssr-prepass": "1.0.8",
-    "release": "6.0.1",
+    "release": "6.2.0",
     "request-promise-core": "1.1.2",
     "rimraf": "2.6.3",
     "selenium-standalone": "6.18.0",

release.js

@@ -0,0 +1,162 @@
+const fetch = require('node-fetch')
+
+// --------------------
+// Repo
+
+const owner = 'vercel'
+const repo = 'next.js'
+
+// --------------------
+// Config
+
+// section -> label
+const sectionLabelMap = {
+  'Core Changes': 'type: next',
+  'Documentation Changes': 'type: documentation',
+  'Example Changes': 'type: example',
+}
+
+const fallbackSection = 'Misc Changes'
+
+// --------------------------------------------------
+
+const prNumberRegex = /\(#([-0-9]+)\)/
+
+const getCommitPullRequest = async (commit) => {
+  const match = prNumberRegex.exec(commit.title)
+
+  if (!match) {
+    return null
+  }
+
+  const number = parseInt(match[1], 10)
+  const url = `https://api.github.com/repos/${owner}/${repo}/pulls/${number}`
+  const res = await fetch(url)
+
+  if (!res.ok) {
+    console.warn(`\n\n⚠️ Failed to fetch PR #${number}\n`)
+    return null
+  }
+
+  return await res.json()
+}
+
+const getSectionForPullRequest = (pullRequest) => {
+  const { labels } = pullRequest
+
+  // sections defined first will take priority
+  for (const [section, label] of Object.entries(sectionLabelMap)) {
+    if (labels.some((prLabel) => prLabel.name === label)) {
+      return section
+    }
+  }
+
+  return null
+}
+
+const groupByLabels = async (commits, github) => {
+  // Initialize the sections object with empty arrays
+  const sections = Object.keys(sectionLabelMap).reduce((sections, section) => {
+    sections[section] = []
+    return sections
+  }, {})
+  sections.__fallback = []
+
+  for (const commit of commits) {
+    const pullRequest = await getCommitPullRequest(commit, github)
+
+    if (pullRequest) {
+      const section = getSectionForPullRequest(pullRequest)
+
+      if (section) {
+        // Add the change to the respective section
+        sections[section].push({
+          title: pullRequest.title,
+          number: pullRequest.number,
+        })
+
+        continue
+      }
+
+      // No section found, add it to the fallback section
+      sections.__fallback.push({
+        title: pullRequest.title,
+        number: pullRequest.number,
+      })
+
+      continue
+    }
+
+    // No Pull Request found, add it to the fallback section but without the number
+    sections.__fallback.push({
+      title: commit.title,
+    })
+  }
+
+  return sections
+}
+
+const buildChangelog = (sections, authors) => {
+  let text = ''
+
+  for (const section in sections) {
+    const changes = sections[section]
+
+    // No changes in this section? Don't render it
+    if (changes.length === 0) {
+      continue
+    }
+
+    const title = section === '__fallback' ? fallbackSection : section
+    text += `### ${title}\n\n`
+
+    for (const change of changes) {
+      const numberText = change.number != null ? `: #${change.number}` : ''
+
+      text += `- ${change.title}${numberText}\n`
+    }
+
+    text += '\n'
+  }
+
+  if (authors.size > 0) {
+    text += '### Credits \n\n'
+    text += 'Huge thanks to '
+
+    let index = 1
+    authors.forEach((author) => {
+      // GitHub links usernames if prefixed with @
+      text += `@${author}`
+
+      const penultimate = index === authors.size - 1
+      const notLast = index !== authors.size
+
+      if (penultimate) {
+        // Oxford comma is applied when list is bigger than 2 names
+        if (authors.size > 2) {
+          text += ','
+        }
+
+        text += ' and '
+      } else if (notLast) {
+        text += ', '
+      }
+
+      index += 1
+    })
+
+    text += ' for helping!'
+    text += '\n'
+  }
+
+  return text
+}
+
+module.exports = async (markdown, metadata) => {
+  const { commits, authors } = metadata
+
+  const sections = await groupByLabels(commits.all)
+  const changelog = buildChangelog(sections, authors)
+
+  return changelog
+}