Add dual CJS/ESM build

.eslintrc.json

@@ -7,11 +7,15 @@
   "extends": ["eslint:recommended", "prettier"],
   "parserOptions": {
     "ecmaVersion": 2018,
-    "sourceType": "module"
+    "sourceType": "script"
   },
-  "rules": {},
-  "globals": {
-    "expect": true,
-    "it": true
-  }
+  "overrides": [
+    {
+      "files": ["src/**/*.js", "__tests__/**/*.mjs"],
+      "parserOptions": {
+        "ecmaVersion": 2020,
+        "sourceType": "module"
+      }
+    }
+  ]
 }

.gitignore

@@ -10,3 +10,6 @@ dump.rdb
 # Coverage reports
 .nyc_output
 coverage
+
+# Build output
+dist

.swcrc.cjs.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "https://swc.rs/schema.json",
+  "jsc": {
+    "parser": {
+      "syntax": "ecmascript",
+      "dynamicImport": true
+    },
+    "target": "es2018",
+    "keepClassNames": true
+  },
+  "module": {
+    "type": "commonjs",
+    "noInterop": false
+  },
+  "sourceMaps": false
+}

.swcrc.esm.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "https://swc.rs/schema.json",
+  "jsc": {
+    "parser": {
+      "syntax": "ecmascript",
+      "dynamicImport": true
+    },
+    "target": "es2018",
+    "keepClassNames": true
+  },
+  "module": {
+    "type": "es6",
+    "strict": false,
+    "noInterop": false
+  },
+  "sourceMaps": false
+}

__tests__/esm-compat.mjs

@@ -0,0 +1,51 @@
+'use strict';
+
+import createAPI from '../dist/esm/index.js';
+import * as utils from '../dist/esm/lib/utils.js';
+import prettyPrint from '../dist/esm/lib/prettyPrint.js';
+import { ApiError } from '../dist/esm/lib/errors.js';
+
+const event = {
+  httpMethod: 'GET',
+  path: '/compat',
+  headers: {},
+  multiValueHeaders: {},
+};
+
+async function main() {
+  const createApi = createAPI({ version: 'v1.0' });
+  createApi.get('/compat', (req, res) => {
+    res.json({ ok: true, method: req.method });
+  });
+
+  const result = await createApi.run(event, {});
+
+  if (typeof createAPI !== 'function') {
+    throw new Error('Expected default export to be a function');
+  }
+
+  if (typeof utils.escapeHtml !== 'function') {
+    throw new Error('Expected utils.escapeHtml to be a function');
+  }
+
+  if (typeof prettyPrint !== 'function') {
+    throw new Error('Expected prettyPrint default export to be a function');
+  }
+
+  if (typeof ApiError !== 'function') {
+    throw new Error('Expected ApiError export to be a function');
+  }
+
+  if (result.statusCode !== 200) {
+    throw new Error(`Expected statusCode 200, received ${result.statusCode}`);
+  }
+
+  if (JSON.parse(result.body).ok !== true) {
+    throw new Error('Expected successful ESM route response');
+  }
+}
+
+main().catch((error) => {
+  console.error(error);
+  process.exit(1);
+});

__tests__/module-compat.unit.js

@@ -0,0 +1,79 @@
+'use strict';
+
+const { execFileSync } = require('child_process');
+const path = require('path');
+
+const event = {
+  httpMethod: 'GET',
+  path: '/compat',
+  headers: {},
+  multiValueHeaders: {},
+};
+
+const runRoute = async (api) => {
+  api.get('/compat', (req, res) => {
+    res.json({ ok: true, method: req.method });
+  });
+
+  return api.run(event, {});
+};
+
+describe('Module Compatibility Tests:', function () {
+  describe('CommonJS build output', function () {
+    it('loads the package factory from dist/cjs', function () {
+      const createAPI = require('../dist/cjs/index.js');
+      expect(typeof createAPI).toBe('function');
+    });
+
+    it('runs a route from dist/cjs', async function () {
+      const createAPI = require('../dist/cjs/index.js');
+      const api = createAPI({ version: 'v1.0' });
+      const result = await runRoute(api);
+
+      expect(result.statusCode).toBe(200);
+      expect(JSON.parse(result.body)).toEqual({ ok: true, method: 'GET' });
+    });
+
+    it('loads deep lib subpaths from dist/cjs', function () {
+      const utils = require('../dist/cjs/lib/utils.js');
+      const errors = require('../dist/cjs/lib/errors.js');
+      const prettyPrint = require('../dist/cjs/lib/prettyPrint.js');
+
+      expect(typeof utils.escapeHtml).toBe('function');
+      expect(typeof errors.ApiError).toBe('function');
+      expect(typeof prettyPrint).toBe('function');
+    });
+  });
+
+  describe('ESM build output', function () {
+    it('passes Node ESM compatibility checks', function () {
+      execFileSync(process.execPath, ['__tests__/esm-compat.mjs'], {
+        cwd: path.join(__dirname, '..'),
+        stdio: 'pipe',
+      });
+    });
+  });
+
+  describe('Package exports resolution', function () {
+    it('resolves the package root and lib subpaths', function () {
+      execFileSync(
+        process.execPath,
+        [
+          '-e',
+          "const { createRequire } = require('module');" +
+            "const packageRequire = createRequire(require('path').resolve('package.json'));" +
+            "const createAPI = packageRequire('.');" +
+            "const utils = packageRequire('lambda-api/lib/utils');" +
+            "const utilsWithExtension = packageRequire('lambda-api/lib/utils.js');" +
+            "if (typeof createAPI !== 'function') throw new Error('Expected package root export to be a function');" +
+            "if (typeof utils.escapeHtml !== 'function') throw new Error('Expected lib/utils export to expose escapeHtml');" +
+            "if (typeof utilsWithExtension.escapeHtml !== 'function') throw new Error('Expected lib/utils.js export to expose escapeHtml');",
+        ],
+        {
+          cwd: path.join(__dirname, '..'),
+          stdio: 'pipe',
+        }
+      );
+    });
+  });
+});

index.test-d.ts

@@ -1,4 +1,4 @@
-import { expectType, expectError } from 'tsd';
+import { expectError, expectType } from 'tsd';
 import {
   API,
   Request,
@@ -19,6 +19,7 @@ import {
   FileError,
   ApiError,
 } from './index';
+import createAPI from './index';
 import {
   APIGatewayProxyEvent,
   APIGatewayProxyEventV2,
@@ -55,6 +56,9 @@ const options: Options = {
 };
 expectType<Options>(options);
 
+const apiFromFactory = createAPI(options);
+expectType<API>(apiFromFactory);
+
 const req = {} as Request;
 expectType<string>(req.method);
 expectType<string>(req.path);
@@ -230,11 +234,7 @@ const invalidTypedHandler: HandlerFunction<
   TypedRequest,
   Response<TypedResponseBody>
 > = (req, res) => {
-  expectError(
-    res.json({
-      hello: req.params.thingId,
-    })
-  );
+  expectError(res.json({ hello: req.params.thingId }));
 };
 api.get<TypedRequest, Response<TypedResponseBody>>(
   '/typed-invalid',

jest.config.js

@@ -0,0 +1,9 @@
+'use strict';
+
+module.exports = {
+  moduleNameMapper: {
+    '^\\.\\./index$': '<rootDir>/dist/cjs/index.js',
+    '^\\.\\./lib/(.*)$': '<rootDir>/dist/cjs/lib/$1.js',
+  },
+  testMatch: ['**/__tests__/**/*.unit.js'],
+};