Config bundling to work for CJS and ESM

esbuild.config.js

@@ -1,49 +1,72 @@
 import fs from 'fs';
-
 import esbuild from 'esbuild';
-
 import packageJson from './package.json' with { type: 'json' };
 
-const buildOptions = {
-  entryPoints: ['./src/index.ts'],
-  bundle: true,
-  outfile: 'dist/index.js',
-  platform: 'node',
-  format: 'cjs',
-  sourcemap: true,
-  target: 'node18',
-  minify: true,
-  treeShaking: true,
-  external: [...Object.keys(packageJson.peerDependencies ?? {}), ...Object.keys(packageJson.dependencies ?? {})],
-  plugins: [
-    {
-      name: 'log-bundle-size',
-      setup(build) {
-        build.onEnd(() => {
-          const filePath = 'dist/index.js';
-          const size = fs.statSync(filePath).size;
-          const sizeInMB = (size / (1024 * 1024)).toFixed(2);
-          console.log(`\nBundle size: ${sizeInMB} MB (${size} bytes)`);
-        });
+const externalDeps = [
+  ...Object.keys(packageJson.peerDependencies ?? {}),
+  ...Object.keys(packageJson.dependencies ?? {}),
+];
+
+const buildFormats = [
+  {
+    format: 'esm',
+    outfile: 'dist/esm/index.js',
+    platform: 'node',
+  },
+  {
+    format: 'cjs',
+    outfile: 'dist/cjs/index.js',
+    platform: 'node',
+  },
+];
+
+function buildForFormat({ format, outfile, platform }) {
+  return esbuild.build({
+    entryPoints: ['./src/index.ts'],
+    bundle: true,
+    outfile,
+    platform,
+    format,
+    sourcemap: true,
+    target: 'node18',
+    minify: true,
+    treeShaking: true,
+    external: externalDeps,
+    metafile: true,
+    plugins: [
+      {
+        name: 'log-bundle-size',
+        setup(build) {
+          build.onEnd(() => {
+            const size = fs.statSync(outfile).size;
+            const sizeInMB = (size / (1024 * 1024)).toFixed(2);
+            console.log(`\n[${format.toUpperCase()}] ${outfile}: ${sizeInMB} MB (${size} bytes)`);
+          });
+        },
       },
-    },
-  ],
-  metafile: true,
-};
+    ],
+  });
+}
+
+async function buildAll() {
+  for (const { format, outfile, platform } of buildFormats) {
+    await buildForFormat({ format, outfile, platform }).then(async (result) => {
+      // Output analysis to console
+      console.log(await esbuild.analyzeMetafile(result.metafile));
+    });
+  }
+}
 
 if (process.argv.includes('--watch')) {
-  // Watch mode
-  esbuild.context(buildOptions).then((context) => {
+  // Watch mode - only build the first format
+  buildForFormat(buildFormats[0]).then((context) => {
     context.watch();
     console.log('Watching for changes...');
   });
 } else {
   // Build mode with analysis
-  esbuild
-    .build(buildOptions)
-    .then(async (result) => {
-      // Output analysis to console
-      console.log(await esbuild.analyzeMetafile(result.metafile));
-    })
-    .catch(() => process.exit(1));
+  buildAll().catch((error) => {
+    console.error(error);
+    process.exit(1);
+  });
 }

package.json

@@ -1,9 +1,13 @@
 {
   "name": "@epilot/pricing",
   "version": "4.52.0",
-  "private": true,
   "description": "Pricing Library",
-  "main": "dist/index.js",
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "exports": {
+    "import": "./dist/esm/index.js",
+    "require": "./dist/cjs/index.js"
+  },
   "types": "dist/index.d.ts",
   "repository": {
     "type": "git",

tsconfig.json

@@ -2,18 +2,19 @@
   "compilerOptions": {
     "rootDir": "src",
     "outDir": "dist",
-    "target": "es2017",
-    "module": "commonjs",
-    "moduleResolution": "node",
+    "target": "ES2020",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
     "lib": ["esnext", "dom"],
     "esModuleInterop": true,
     "noImplicitAny": true,
     "noUnusedLocals": true,
     "sourceMap": false,
     "declaration": true,
     "skipLibCheck": true,
-    "strict": true
+    "strict": true,
+    "emitDeclarationOnly": true
   },
   "include": ["src/**/*"],
-  "exclude": ["node_modules"]
+  "exclude": ["node_modules", "dist", "**/*.test.ts", "**/__tests__"]
 }