From 34a0cfabc4bdc36803dfbb502f0f46704993a76b Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=B4me=20Benoit?= <jerome.benoit@sap.com>
Date: Sat, 18 Mar 2023 16:29:45 +0100
Subject: [PATCH] feat: initial work at bundling ESM and CommonJS
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Signed-off-by: Jérôme Benoit <jerome.benoit@sap.com>
---
 package.json               |  5 ++++-
 rollup.config.mjs          | 32 ++++++++++++++++++++++++--------
 src/pools/abstract-pool.ts |  2 +-
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/package.json b/package.json
index 65e34365..c06db4c5 100644
--- a/package.json
+++ b/package.json
@@ -3,7 +3,10 @@
   "version": "2.3.8",
   "description": "A fast, easy to use Node.js Worker Thread Pool and Cluster Pool implementation",
   "license": "MIT",
-  "main": "lib/index.js",
+  "exports": [
+    "lib/index.js",
+    "lib/index.mjs"
+  ],
   "scripts": {
     "prepare": "node prepare.js",
     "build": "rollup --config --environment BUILD:development",
diff --git a/rollup.config.mjs b/rollup.config.mjs
index e1bdac21..8997445e 100644
--- a/rollup.config.mjs
+++ b/rollup.config.mjs
@@ -10,14 +10,30 @@ const isDocumentation = process.env.DOCUMENTATION
 
 export default {
   input: 'src/index.ts',
-  output: {
-    ...(isDevelopmentBuild ? { dir: 'lib' } : { file: 'lib/index.js' }),
-    format: 'cjs',
-    sourcemap: !!isDevelopmentBuild,
-    ...(isDevelopmentBuild && { preserveModules: true }),
-    ...(isDevelopmentBuild && { preserveModulesRoot: 'src' }),
-    ...(!isDevelopmentBuild && { plugins: [terser({ maxWorkers: 2 })] })
-  },
+  output: [
+    {
+      ...(isDevelopmentBuild ? { dir: 'lib' } : { file: 'lib/index.js' }),
+      format: 'cjs',
+      sourcemap: !!isDevelopmentBuild,
+      ...(isDevelopmentBuild && {
+        preserveModules: true,
+        preserveModulesRoot: 'src'
+      }),
+      ...(!isDevelopmentBuild && { plugins: [terser({ maxWorkers: 2 })] })
+    },
+    {
+      ...(isDevelopmentBuild ? { dir: 'lib' } : { file: 'lib/index.mjs' }),
+      format: 'esm',
+      sourcemap: !!isDevelopmentBuild,
+
+      ...(isDevelopmentBuild && {
+        entryFileNames: '[name].mjs',
+        preserveModules: true,
+        preserveModulesRoot: 'src'
+      }),
+      ...(!isDevelopmentBuild && { plugins: [terser({ maxWorkers: 2 })] })
+    }
+  ],
   external: ['async_hooks', 'cluster', 'events', 'os', 'worker_threads'],
   plugins: [
     typescript({
diff --git a/src/pools/abstract-pool.ts b/src/pools/abstract-pool.ts
index 695c43b3..32b4d983 100644
--- a/src/pools/abstract-pool.ts
+++ b/src/pools/abstract-pool.ts
@@ -3,7 +3,7 @@ import type {
   PromiseWorkerResponseWrapper
 } from '../utility-types'
 import { EMPTY_FUNCTION, EMPTY_OBJECT_LITERAL } from '../utils'
-import { isKillBehavior, KillBehaviors } from '../worker/worker-options'
+import { KillBehaviors, isKillBehavior } from '../worker/worker-options'
 import type { PoolOptions } from './pool'
 import { PoolEmitter } from './pool'
 import type { IPoolInternal, TasksUsage } from './pool-internal'
-- 
2.34.1