WIP: multi-build support for both commonjs and ESM

.dockerignore

@@ -6,3 +6,4 @@ elasticsearch
 lib
 junit-output
 .tap
+esm

.gitignore

@@ -68,3 +68,4 @@ bun.lockb
 test-results
 processinfo
 .tap
+esm

index.mjs

@@ -0,0 +1,53 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import {
+  Diagnostic,
+  Transport,
+  WeightedConnectionPool,
+  ClusterConnectionPool,
+  BaseConnectionPool,
+  CloudConnectionPool,
+  BaseConnection,
+  HttpConnection,
+  UndiciConnection,
+  Serializer,
+  errors,
+  events
+} from '@elastic/transport'
+
+import * as Client from './esm/client'
+import * as SniffingTransport from './esm/sniffingTransport'
+
+export {
+  Client,
+  SniffingTransport,
+  Diagnostic,
+  Transport,
+  WeightedConnectionPool,
+  ClusterConnectionPool,
+  BaseConnectionPool,
+  CloudConnectionPool,
+  BaseConnection,
+  HttpConnection,
+  UndiciConnection,
+  Serializer,
+  errors,
+  events
+}

package.json

@@ -3,13 +3,18 @@
   "version": "9.0.0-alpha.4",
   "versionCanary": "9.0.0-canary.0",
   "description": "The official Elasticsearch client for Node.js",
+  "type": "module",
   "main": "./index.js",
-  "types": "index.d.ts",
+  "module": "./index.mjs",
   "exports": {
-    "require": "./index.js",
-    "import": "./index.js",
-    "types": "./index.d.ts"
+    ".": {
+      "require": "./index.js",
+      "import": "./index.mjs"
+    },
+    "./lib/*": "./lib/*.js",
+    "./esm/*": "./esm/*.js"
   },
+  "types": "index.d.ts",
   "scripts": {
     "test": "npm run build && npm run lint && tap",
     "test:unit": "npm run build && tap",
@@ -23,8 +28,10 @@
     "lint:fix": "ts-standard --fix src",
     "license-checker": "license-checker --production --onlyAllow='MIT;Apache-2.0;Apache1.1;ISC;BSD-3-Clause;BSD-2-Clause;0BSD'",
     "prebuild": "npm run clean-build && npm run lint",
-    "build": "tsc && rm lib/package.json && mv lib/src/* lib/ && rm -rf lib/src",
-    "clean-build": "rimraf ./lib && mkdir lib",
+    "build": "npm run build:cjs && npm run build:esm",
+    "build:cjs": "tsc --project ./tsconfig.cjs.json && rm lib/package.json && mv lib/src/* lib/ && rm -rf lib/src",
+    "build:esm": "tsc --project ./tsconfig.esm.json && rm esm/package.json && mv esm/src/* esm/ && rm -rf esm/src",
+    "clean-build": "rimraf ./lib && mkdir lib; rimraf ./esm && mkdir esm",
     "prepublishOnly": "npm run build"
   },
   "keywords": [

tsconfig.cjs.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "commonjs",
+    "moduleResolution": "node16",
+    "outDir": "lib"
+  }
+}

tsconfig.esm.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "ESNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "esm"
+  }
+}

tsconfig.json

@@ -1,8 +1,7 @@
 {
+  "$schema": "https://json.schemastore.org/tsconfig",
   "compilerOptions": {
-    "target": "ES2019",
-    "module": "commonjs",
-    "moduleResolution": "node",
+    "target": "es2022",
     "declaration": true,
     "pretty": true,
     "noEmitOnError": true,
@@ -15,13 +14,12 @@
     "noFallthroughCasesInSwitch": true,
     "useDefineForClassFields": true,
     "forceConsistentCasingInFileNames": true,
-    "skipLibCheck": false,
+    "skipLibCheck": true,
     "esModuleInterop": true,
     "isolatedModules": true,
     "importHelpers": true,
-    "outDir": "lib",
     "lib": [
-      "ES2019",
+      "es2023",
       "dom"
     ]
   },