feat: 🎸 add back Lerna support

lib/defaults.js

@@ -79,7 +79,7 @@ const questions = [
   'body',
   'breaking',
   'issues',
-  // 'lerna'
+  'lerna'
 ];
 
 module.exports = {

lib/questions/lerna.js

@@ -1,6 +1,9 @@
+const {getAllPackages, getChangedPackages} = require('../util/lerna');
+
 exports.createQuestion = (state) => {
+  const changedPackages = getChangedPackages(state);
   const question = {
-    choices: allPackages,
+    choices: getAllPackages(state),
     default: changedPackages,
     message: `The packages that this commit has affected (${changedPackages.length} detected)\n`,
     name: 'packages',

lib/util/lerna.js

@@ -0,0 +1,52 @@
+const {execSync} = require('child_process');
+const path = require('path');
+const fs = require('fs');
+
+const isDir = (root) => (name) => {
+  const filepath = path.join(root, name);
+
+  try {
+    const stats = fs.statSync(filepath);
+
+    return stats.isDirectory();
+  } catch (error) {
+    return false;
+  }
+};
+
+const getAllPackages = (state) => {
+  try {
+    const dir = path.join(state.root, 'packages');
+
+    return fs.readdirSync(dir).map(isDir(dir));
+  } catch (error) {
+    return [];
+  }
+};
+
+const getChangedFiles = () =>
+  execSync('git diff --cached --name-only 2>/dev/null')
+    .toString()
+    .trim()
+    .split('\n');
+
+const getChangedPackages = () => {
+  const unique = {};
+  const changedFiles = getChangedFiles();
+  const regex = /^packages\/([^/]+)\//;
+
+  for (const filename of changedFiles) {
+    const matches = filename.match(regex);
+
+    if (matches) {
+      unique[matches[1]] = 1;
+    }
+  }
+
+  return Object.keys(unique);
+};
+
+module.exports = {
+  getAllPackages,
+  getChangedPackages
+};