chore: emit granular esm

package.json

@@ -2,9 +2,9 @@
   "name": "@mswjs/source",
   "version": "0.0.0",
   "description": "Generate MSW request handlers from OpenAPI documents, HAR archives, and other sources.",
-  "main": "./lib/index.js",
-  "module": "./lib/index.mjs",
-  "types": "./lib/index.d.ts",
+  "main": "./lib/cjs/index.js",
+  "module": "./lib/esm/index.mjs",
+  "types": "./lib/cjs/index.d.ts",
   "exports": {
     ".": {
       "require": "./lib/index.cjs",

tsup.config.ts

@@ -1,10 +1,28 @@
-import { defineConfig } from 'tsup'
+import { defineConfig, Options } from 'tsup'
 
-export default defineConfig({
-  entry: ['src/index.ts'],
-  format: ['esm', 'cjs'],
-  outDir: './lib',
+const commonOptions = {
   clean: true,
+  sourcemap: true,
   tsconfig: './tsconfig.build.json',
   // dts: true,
+} satisfies Options
+
+const esm = defineConfig({
+  entry: ['src/**/*.ts'],
+  format: 'esm',
+  outDir: './lib/esm',
+  bundle: false,
+  splitting: true,
+  ...commonOptions,
+})
+
+const cjs = defineConfig({
+  entry: ['src/index.ts'],
+  format: 'cjs',
+  outDir: './lib/cjs',
+  bundle: true,
+  splitting: false,
+  ...commonOptions,
 })
+
+export default [esm, cjs]