Introduce Release script (#4631)

scripts/release/steps/update-changelog.js

@@ -0,0 +1,100 @@
+"use strict";
+
+const chalk = require("chalk");
+const dedent = require("dedent");
+const fs = require("fs");
+const prsMergedSince = require("prs-merged-since");
+const semver = require("semver");
+const { logPromise, waitForEnter } = require("../utils");
+
+function getBlogPostInfo(version) {
+  const date = new Date();
+  const year = date.getFullYear();
+  const month = new String(date.getMonth() + 1).padStart(2, "0");
+  const day = new String(date.getDate()).padStart(2, "0");
+
+  return {
+    file: `website/blog/${year}-${month}-${day}-${version}.md`,
+    path: `blog/${year}/${month}/${day}/${version}.html`
+  };
+}
+
+async function getMergedPrs(previousVersion) {
+  const prs = await prsMergedSince({
+    repo: "prettier/prettier",
+    tag: previousVersion,
+    githubApiToken: process.env.GITHUB_API_TOKEN
+  });
+  return prs
+    .map(pr => `- ${pr.title} ([#${pr.number}](${pr.html_url}))`)
+    .join("\n");
+}
+
+function writeChangelog({ version, previousVersion, releaseNotes }) {
+  const changelog = fs.readFileSync("CHANGELOG.md", "utf-8");
+  const newEntry = dedent`
+    # ${version}
+
+    [link](https://github.com/prettier/prettier/compare/${previousVersion}...${version})
+
+    ${releaseNotes}
+  `;
+  fs.writeFileSync("CHANGELOG.md", newEntry + "\n\n" + changelog);
+}
+
+module.exports = async function({ version, previousVersion }) {
+  const semverDiff = semver.diff(version, previousVersion);
+
+  if (semverDiff !== "patch") {
+    const blogPost = getBlogPostInfo(version);
+    writeChangelog({
+      version,
+      previousVersion,
+      releaseNotes: `- [Release Notes](https://prettier.io/${blogPost.path})`
+    });
+    if (fs.existsSync(blogPost.file)) {
+      // Everything is fine, this step is finished
+      return;
+    }
+    console.warn(
+      dedent(chalk`
+        {yellow warning} The file {bold ${
+          blogPost.file
+        }} doesn't exist, but it will be referenced in {bold CHANGELOG.md}. Make sure to create it later.
+
+        Press ENTER to continue.
+      `)
+    );
+  } else {
+    if (!process.env.GITHUB_API_TOKEN) {
+      console.log(
+        chalk`{yellow warning} GitHub API access token missing. You can expose a token via {bold GITHUB_API_TOKEN} environment variable.`
+      );
+    }
+
+    const releaseNotes = await logPromise(
+      "Fetching merged PRs",
+      getMergedPrs(previousVersion)
+    );
+    writeChangelog({
+      version,
+      previousVersion,
+      releaseNotes
+    });
+    console.log();
+    console.log(
+      dedent(chalk`
+        {yellow.bold A manual step is necessary.}
+
+        The script has updated the file {bold CHANGELOG.md} with all the merged PRs since the last release.
+        You must edit it to focus only on relevant changes and make sure they have meaningful titles.
+
+        You don't need to commit the file, the script will take care of that.
+
+        When you're finished, press ENTER to continue.
+      `)
+    );
+  }
+
+  await waitForEnter();
+};