fix: Output both cjs and esm modules

Author: Michael Dowse

package.json

@@ -2,17 +2,20 @@
   "name": "@michaeldowseza/hello-world",
   "version": "1.0.0",
   "description": "Hello world",
-  "main": "lib/index.js",
-  "types": "lib/index.d.ts",
   "files": [
     "lib/"
   ],
   "scripts": {
     "lint": "eslint . --ext .ts",
     "test": "jest --coverage",
     "prepublishOnly": "npm run build",
-    "build": "tsc -p tsconfig.json"
+    "build": "npm run build:esm && npm run build:cjs",
+    "build:esm": "tsc",
+    "build:cjs": "tsc --module commonjs --outDir lib/cjs"
   },
+  "main": "./lib/cjs/index.js",
+  "module": "./lib/esm/index.js",
+  "types": "./lib/esm/index.d.ts",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/michaeldowseza/hello-world.git"

tsconfig.json

@@ -1,14 +1,16 @@
 {
   "compilerOptions": {
-    "target": "ESNext",
-    "module": "CommonJS",
+    "outDir": "lib/esm",
+    "target": "es5",
+    "lib": ["es6", "es2016", "es2017"],
+    "module": "esnext",
     "strict": true,
     "esModuleInterop": true,
     "forceConsistentCasingInFileNames": true,
     "declaration": true,
-    "outDir": "lib",
     "moduleResolution": "node",
     "types": ["node", "jest"]
   },
-  "include": ["src"]
+  "include": ["src"],
+  "exclude": ["node_modules", "lib"]
 }