Switched to type: module.

scripts/merge-messages.js

@@ -0,0 +1,42 @@
+/* eslint-disable no-console */
+import fs from 'node:fs';
+import path from 'node:path';
+import prettier from 'prettier';
+import messages from '../build/extracted-messages.json';
+import { createRequire } from 'module';
+
+const require = createRequire(import.meta.url);
+const dest = path.resolve(process.cwd(), 'src/lang');
+const files = fs.readdirSync(dest);
+const keys = Object.keys(messages).sort();
+
+/*
+This script takes extracted messages and merges them
+with the existing files under `lang`. Any newly added
+keys will be printed to the console.
+ */
+files.forEach(file => {
+  const lang = require(path.resolve(process.cwd(), `src/lang/${file}`));
+
+  console.log(`Merging ${file}`);
+
+  const merged = keys.reduce((obj, key) => {
+    const message = lang[key];
+
+    if (file === 'en-US.json') {
+      obj[key] = messages[key].defaultMessage;
+    } else {
+      obj[key] = message || messages[key].defaultMessage;
+    }
+
+    if (!message) {
+      console.log(`* Added key ${key}`);
+    }
+
+    return obj;
+  }, {});
+
+  const json = prettier.format(JSON.stringify(merged), { parser: 'json' });
+
+  fs.writeFileSync(path.resolve(dest, file), json);
+});