1 files changed, 10 insertions, 7 deletions

diff --git a/config/esbuild-config.js b/config/esbuild-config.js
index 9140b89..52d1a59 100644
--- a/config/esbuild-config.js
+++ b/config/esbuild-config.js
@@ -1,6 +1,4 @@
-// @ts-check
-
-const { banner } = require('./build-common');
+import { banner } from './build-common.js';
 
 /** @type {string} */
 const mode = process.env.MODE || 'development';
@@ -8,8 +6,10 @@ const mode = process.env.MODE || 'development';
 /** @type {boolean} */
 const isDevelopment = mode === 'development';
 
+/** @type {string} */
 const modeString = JSON.stringify(mode);
 
+/** @type {Record<string, string>} */
 const defineEnv = {
   'import.meta.env.DEV': JSON.stringify(isDevelopment),
   'import.meta.env.MODE': modeString,
@@ -20,13 +20,16 @@ const defineEnv = {
 
 /**
  * @param {import('esbuild').BuildOptions} config
- * @param {object | unknown} metaEnvVars
+ * @param {Record<string, string>} [metaEnvVars]
  * @returns {import('esbuild').BuildOptions}
  */
-module.exports.getConfig = function(config, metaEnvVars) {
+export function getConfig(config, metaEnvVars) {
+  /** @type {Record<string, string>} */
   const defineMeta = {};
-  for (const varName in metaEnvVars) {
-    defineMeta[`import.meta.env.${varName}`] = JSON.stringify(metaEnvVars[varName]);
+  if (metaEnvVars) {
+    for (const varName in metaEnvVars) {
+      defineMeta[`import.meta.env.${varName}`] = JSON.stringify(metaEnvVars[varName]);
+    }
   }
   return {
     logLevel: 'info',