feat!: migrate package to ESM modules for modern JavaScript compatibility

Converted the package from CommonJS to ESM to align with modern JavaScript standards and improve tree-shaking capabilities. Added esbuild transpilation for Lambda environments to maintain backwards compatibility.

BREAKING CHANGE: Package now uses ESM modules. Consumers must use ESM imports or update their build configuration to handle ESM packages.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: vladholubiev

.gitignore

@@ -26,8 +26,10 @@ yarn.lock
 .idea/.gitignore
 !.husky/_/husky.sh
 
-./test/cid
-./test/lib
-./test/node_modules
+test/cid
+test/lib
+test/node_modules
+test/dist/
+test/test-bundled.js
 
 .DS_Store

jest.config.mjs

@@ -2,10 +2,11 @@
  * @type {import('jest').Config}
  */
 const config = {
+  extensionsToTreatAsEsm: ['.ts'],
   transform: {
     '^.+\\.(t|j)sx?$': '@swc/jest',
   },
-  transformIgnorePatterns: ['node_modules/(?!(is-video|@shelf/is-audio-filepath)/)'],
+  transformIgnorePatterns: ['node_modules/(?!(is-video|@shelf/is-audio-filepath|is-image)/)'],
   resetMocks: true,
   coverageThreshold: {
     global: {

package.json

@@ -15,8 +15,15 @@
     "email": "vlad@shelf.io",
     "url": "https://shelf.io"
   },
-  "main": "lib",
+  "type": "module",
+  "main": "lib/index.js",
   "types": "lib/index.d.ts",
+  "exports": {
+    ".": {
+      "import": "./lib/index.js",
+      "types": "./lib/index.d.ts"
+    }
+  },
   "files": [
     "lib"
   ],
@@ -40,9 +47,9 @@
   },
   "prettier": "@shelf/prettier-config",
   "dependencies": {
-    "@shelf/is-audio-filepath": "2.0.0",
-    "del": "6.0.0",
-    "is-image": "3.1.0",
+    "@shelf/is-audio-filepath": "3.0.1",
+    "del": "8.0.0",
+    "is-image": "4.0.0",
     "is-video": "2.0.0"
   },
   "devDependencies": {
@@ -52,10 +59,11 @@
     "@swc/jest": "0.2.39",
     "@types/jest": "30.0.0",
     "@types/node": "^24.2.1",
+    "esbuild": "0.25.9",
     "eslint": "9.33.0",
-    "husky": "8.0.3",
+    "husky": "9.1.7",
     "jest": "30.0.5",
-    "lint-staged": "13.3.0",
+    "lint-staged": "16.1.5",
     "prettier": "3.6.2",
     "typescript": "5.9.2"
   },

src/cleanup.ts

@@ -1,13 +1,13 @@
 import fs from 'fs/promises';
-import del from 'del';
+import {deleteAsync} from 'del';
 
 // Removes temp files generated by LibreOffice
 export async function cleanupTempFiles(): Promise<void> {
   const files = await fs.readdir(`/tmp`);
   for (const file of files) {
     if (file.endsWith('.tmp') === true || file.startsWith('OSL_PIPE')) {
       try {
-        await del([`/tmp/${file}`, `/tmp/${file}/*`], {force: true});
+        await deleteAsync([`/tmp/${file}`, `/tmp/${file}/*`], {force: true});
       } catch {}
     }
   }

src/convert.ts

@@ -1,8 +1,8 @@
 import childProcess from 'child_process';
 import util from 'util';
 import path from 'node:path';
-import {cleanupTempFiles} from './cleanup';
-import {getConvertedFilePath} from './logs';
+import {cleanupTempFiles} from './cleanup.js';
+import {getConvertedFilePath} from './logs.js';
 
 const exec = util.promisify(childProcess.exec);
 

src/index.ts

@@ -1,2 +1,2 @@
-export * from './convert';
-export * from './validations';
+export * from './convert.js';
+export * from './validations.js';

test/Dockerfile

@@ -1,4 +1,4 @@
-FROM public.ecr.aws/shelf/lambda-libreoffice-base:7.6-node18-x86_64
+FROM public.ecr.aws/shelf/lambda-libreoffice-base:7.6-node20-x86_64
 
-COPY . ${LAMBDA_TASK_ROOT}/
+COPY test-bundled.js ${LAMBDA_TASK_ROOT}/test.js
 CMD [ "test.handler" ]

test/build-for-lambda.js

@@ -0,0 +1,28 @@
+#!/usr/bin/env node
+import {existsSync, mkdirSync} from 'fs';
+import * as esbuild from 'esbuild';
+
+if (!existsSync('./dist')) {
+  mkdirSync('./dist');
+}
+
+await esbuild.build({
+  entryPoints: ['./test.js'],
+  bundle: true,
+  outfile: './dist/test.js',
+  platform: 'node',
+  target: 'node20',
+  format: 'cjs',
+  external: [
+    // Keep native modules external
+    'child_process',
+    'fs',
+    'fs/promises',
+    'path',
+    'util',
+    'node:path',
+  ],
+  logLevel: 'info',
+});
+
+console.log('Lambda handler built successfully to ./dist/test.js');

test/test.js

@@ -1,5 +1,5 @@
 import {writeFileSync} from 'fs';
-import {convertTo} from './lib';
+import {convertTo} from './lib/index.js';
 
 export const handler = async () => {
   writeFileSync('/tmp/test.txt', Buffer.from('Hello World!'));

test/test.sh

@@ -1,10 +1,16 @@
 #!/usr/bin/env bash
 
+# Build the ESM code to CommonJS for Lambda compatibility
+echo "Building Lambda handler with esbuild..."
 cp -r ../lib ./
-cp -r ../node_modules ./
-docker build -t lo-lambda-test .
+node build-for-lambda.js
+
+# Copy the transpiled file to the root for the Dockerfile
+cp ./dist/test.js ./test-bundled.js
+
+podman build --platform linux/amd64 -t lo-lambda-test .
 
 (sleep 7; curl -XPOST "http://localhost:9000/2015-03-31/functions/function/invocations" -d '{"payload":"hello world!"}') &
-(sleep 30; CID=$(cat ./cid) && docker stop $CID && rm ./cid) &
+(sleep 30; CID=$(cat ./cid) && podman stop $CID && rm ./cid) &
 
-docker run -p 9000:8080 --rm --cidfile ./cid lo-lambda-test
+podman run --platform linux/amd64 -p 9000:8080 --rm --cidfile ./cid lo-lambda-test