chore: use tsup for building; package.json exports for better compat

package.json

@@ -9,19 +9,29 @@
   "author": "James M Snell <jasnell@gmail.com>",
   "license": "MIT",
   "main": "./dist/lib/index.js",
+  "module": "./dist/lib/index.mjs",
+  "types": "./dist/lib/index.d.ts",
   "exports": {
-    "import": "./dist/esm-wrapper.mjs",
-    "require": "./dist/lib/index.js"
+    ".": {
+      "import": {
+        "types": "./dist/lib/index.d.mts",
+        "default": "./dist/lib/index.mjs"
+      },
+      "require": {
+        "types": "./dist/lib/index.d.ts",
+        "default": "./dist/lib/index.js"
+      },
+      "types": "./dist/lib/index.d.ts",
+      "default": "./dist/lib/index.js"
+    }
   },
-  "types": "./dist/lib/index.d.ts",
   "scripts": {
     "prebuildify": "prebuildify --napi --strip",
     "install": "node-gyp-build",
-    "build": "npm run prebuildify && tsc && npm run gen-esm-wrapper",
+    "build": "npm run prebuildify && tsup",
     "lint": "standardx \"**/*.{ts,mjs,js,cjs}\" | snazzy",
     "test-only": "tap --ts",
     "test": "npm run lint && npm run build && npm run test-only",
-    "gen-esm-wrapper": "gen-esm-wrapper . dist/esm-wrapper.mjs",
     "prepack": "npm run build"
   },
   "repository": {
@@ -58,12 +68,12 @@
     "@typescript-eslint/eslint-plugin": "^6.14.0",
     "@typescript-eslint/parser": "^6.14.0",
     "abort-controller": "^3.0.0",
-    "gen-esm-wrapper": "^1.1.3",
     "prebuildify": "^6.0.1",
     "snazzy": "^9.0.0",
     "standardx": "^7.0.0",
     "tap": "^15.0.6",
     "ts-node": "^10.9.2",
+    "tsup": "^8.2.4",
     "typescript": "^5.3.3"
   },
   "dependencies": {

tsconfig.json

@@ -20,5 +20,5 @@
     "resolveJsonModule": true,                /* Include modules imported with '.json' extension */
     "forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */
   },
-  "include": ["lib"],
+  "include": ["lib", "tsup.config.ts"],
 }

tsup.config.ts

@@ -0,0 +1,21 @@
+import { defineConfig } from "tsup";
+import { copyFile } from "node:fs/promises";
+import { join } from "node:path";
+
+export default defineConfig({
+  outDir: "dist/lib",
+  entry: ["./lib/index.ts"],
+  format: ["cjs", "esm"],
+  target: "node18",
+  sourcemap: true,
+  clean: true,
+  minify: false,
+  shims: true,
+  dts: true,
+  async onSuccess() {
+    await copyFile(
+      join(__dirname, "package.json"),
+      join(__dirname, "dist/package.json"),
+    );
+  },
+});