Convert to ES Modules (#144)

.eslintrc.cjs

@@ -0,0 +1,26 @@
+module.exports = {
+  root: true,
+  parser: '@typescript-eslint/parser',
+  plugins: ['sort-destructure-keys'],
+  env: {
+    es6: true,
+    node: true,
+  },
+  extends: [
+    'eslint:recommended',
+    'plugin:import/recommended',
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ],
+  parserOptions: {
+    ecmaVersion: 'latest',
+    sourceType: 'module',
+  },
+  rules: {
+    'sort-destructure-keys/sort-destructure-keys': 'error',
+    '@typescript-eslint/no-unused-vars': [
+      'error',
+      { varsIgnorePattern: 'unused' },
+    ],
+  },
+};

.prettierrc.json

@@ -0,0 +1,4 @@
+{
+  "singleQuote": true,
+  "trailingComma": "es5"
+}

app.js

@@ -14,21 +14,22 @@
  * limitations under the License.
  */
 
-const express = require('express');
-const { StatusCodes } = require('http-status-codes');
+import express from 'express';
+import { StatusCodes } from 'http-status-codes';
 
-const errorTracker = require('./routes/error-tracker');
-const parseErrorHandling = require('./utils/requests/parse-error-handling');
+import errorTracker from './routes/error-tracker.js';
+import parseErrorHandling from './utils/requests/parse-error-handling.js';
 
-const app = express();
 const BODY_LIMIT = 10 * 1024; /* 10kb */
+const jsonParser = express.json({
+  limit: BODY_LIMIT,
+  type: () => true,
+});
+
+const app = express();
 function rawJsonBodyParserMiddleware(req, res, next) {
   if (!req.rawBody) {
     // Defer to bodyParser when running as a server.
-    jsonParser = express.json({
-      limit: BODY_LIMIT,
-      type: () => true,
-    });
     jsonParser(req, res, next);
   } else if (req.rawBody.length > BODY_LIMIT) {
     // When Cloud Functions hijacks the request, validate and parse it manually.
@@ -55,4 +56,4 @@ app.post('*', (req, res) => {
   return errorTracker(req, res);
 });
 
-module.exports = app;
+export default app;

index.js

@@ -14,5 +14,6 @@
  * limitations under the License.
  */
 
-const app = require('./app');
-module.exports = { app };
+import app from './app.js';
+
+export { app };