support cjs

note: esbuild doesn't have a config like most tooling.  They suggest
instead to use their api.  See
evanw/esbuild#952 (comment)

.gitignore

@@ -18,3 +18,6 @@ pnpm-lock.yaml
 
 output.json
 deno.lock
+
+bundle.cjs
+bundle.cjs.map

build.js

@@ -0,0 +1,20 @@
+import { build } from 'esbuild'
+import fs from 'fs'
+
+const { dependencies } = JSON.parse(fs.readFileSync('./package.json', 'utf8'))
+// we need esbuild to process esm dependencies while leaving cjs compatible ones
+// out of the bundle
+const esmDependencies = new Set(['bellajs'])
+const externalDeps = Object.keys(dependencies)
+  .filter(dep => !esmDependencies.has(dep))
+
+build({
+  entryPoints: ['./src/main.js'],
+  bundle: true,
+  platform: 'node',
+  target: 'node16',
+  outfile: 'bundle.cjs',
+  minify: true,
+  sourcemap: true,
+  external: externalDeps,
+})

package.json

@@ -10,6 +10,14 @@
   "author": "@extractus",
   "main": "./src/main.js",
   "type": "module",
+  "exports": {
+    ".": {
+      "types": "./index.d.ts",
+      "import": "./src/main.js",
+      "require": "./bundle.cjs",
+      "default": "./src/main.js"
+    }
+  },
   "imports": {
     "cross-fetch": "./src/deno/cross-fetch.js"
   },
@@ -23,6 +31,7 @@
   "scripts": {
     "lint": "eslint .",
     "lint:fix": "eslint --fix .",
+    "build": "node build",
     "pretest": "npm run lint",
     "test": "NODE_ENV=test NODE_OPTIONS=--experimental-vm-modules jest --verbose --coverage=true",
     "eval": "node eval",
@@ -35,6 +44,7 @@
     "html-entities": "^2.4.0"
   },
   "devDependencies": {
+    "esbuild": "^0.19.8",
     "eslint": "^8.53.0",
     "https-proxy-agent": "^7.0.2",
     "jest": "^29.7.0",