chore: add yarn-lock-diff helper

scripts/yarn-lock-diff.mjs

@@ -0,0 +1,105 @@
+import { exec } from 'child_process';
+import fs from 'fs';
+// eslint-disable-next-line import/no-extraneous-dependencies
+import lockfile from '@yarnpkg/lockfile';
+
+/**
+ * === Generic Helpers ===
+ */
+
+const execPromise = cmd =>
+  new Promise(resolve => exec(cmd, { maxBuffer: 200000000 }, (err, stdout) => resolve(stdout)));
+
+const arrDiff = (arrA, arrB, eq = (a, b) => a === b) =>
+  arrA.filter(a => arrB.every(b => !eq(a, b)));
+
+/**
+ * === yarn-lock-diff ===
+ */
+
+function groupByPackageName(obj) {
+  const packages = [];
+  Object.keys(obj.object).forEach(key => {
+    const names = key.split('@');
+    let name = names[0];
+    if (name === '') {
+      // handle scoped packages
+      name = `@${names[1]}`;
+    }
+    const { version } = obj.object[key];
+    const found = packages.find(p => p.name === name);
+    if (found) {
+      found.versions.push(version);
+    } else {
+      packages.push({
+        name,
+        versions: [version],
+      });
+    }
+  });
+  return packages;
+}
+
+function yarnLockDiff(prevLockContents, curLockContents) {
+  const previous = lockfile.parse(prevLockContents);
+  const current = lockfile.parse(curLockContents);
+
+  const previousPackages = groupByPackageName(previous);
+  const currentPackages = groupByPackageName(current);
+
+  const removedResult = [];
+  const changedResult = [];
+
+  previousPackages.forEach(prevPkg => {
+    const foundCurPkg = currentPackages.find(curPkg => curPkg.name === prevPkg.name);
+    if (!foundCurPkg) {
+      removedResult.push(prevPkg);
+    } else {
+      const diff = arrDiff(foundCurPkg.versions, prevPkg.versions);
+      if (diff.length) {
+        changedResult.push({
+          name: prevPkg.name,
+          previousVersions: Array.from(new Set(prevPkg.versions)),
+          currentVersions: Array.from(new Set(foundCurPkg.versions)),
+          diff,
+        });
+      }
+    }
+  });
+  return { removed: removedResult, changed: changedResult };
+}
+
+/**
+ * === cli ===
+ */
+
+function getArgs() {
+  const idx = process.argv.findIndex(a => a === '--versions-back');
+  let versionsBack;
+  if (idx > 0) {
+    versionsBack = Number(process.argv[idx + 1]);
+    if (Number.isNaN(versionsBack)) {
+      throw new Error('Please provide a number for --versions-back');
+    }
+  } else {
+    versionsBack = 1;
+  }
+  return { versionsBack };
+}
+
+async function main() {
+  const { versionsBack } = getArgs();
+  const changeHistory = await execPromise(`git log yarn.lock`);
+  const commits = changeHistory
+    .match(/commit (.*)\n/g)
+    .map(c => c.replace('commit ', '').replace('\n', ''));
+
+  // For now, we pick latest commit. When needed in the future, allow '--age 2-months' or smth
+  const prevLockContents = await execPromise(`git show ${commits[versionsBack - 1]}:yarn.lock`);
+  const curLockContents = await fs.promises.readFile('yarn.lock', 'utf8');
+
+  // eslint-disable-next-line no-console
+  console.log(JSON.stringify(yarnLockDiff(prevLockContents, curLockContents), null, 2));
+}
+
+main();