fix: improve compatibility with node16 module resolution (#711)

Related:

- microsoft/TypeScript#46770 (comment)
- socketio/socket.io-client#1589

Author: tylerbutler

package.json

@@ -12,14 +12,24 @@
     "./dist/engine.io.min.js": "./dist/engine.io.min.js",
     ".": {
       "import": {
+        "types": "./build/esm/index.d.ts",
         "node": "./build/esm-debug/index.js",
         "default": "./build/esm/index.js"
       },
-      "require": "./build/cjs/index.js"
+      "require": {
+        "types": "./build/cjs/index.d.ts",
+        "default": "./build/cjs/index.js"
+      }
     },
     "./debug": {
-      "import": "./build/esm-debug/index.js",
-      "require": "./build/cjs/index.js"
+      "import": {
+        "types": "./build/esm/index.d.ts",
+        "default": "./build/esm-debug/index.js"
+      },
+      "require": {
+        "types": "./build/cjs/index.d.ts",
+        "default": "./build/cjs/index.js"
+      }
     }
   },
   "types": "build/esm/index.d.ts",

tsconfig.json

@@ -3,7 +3,7 @@
     "outDir": "build/cjs/",
     "target": "es2018", // Node.js 10 (https://github.com/microsoft/TypeScript/wiki/Node-Target-Mapping)
     "module": "commonjs",
-    "declaration": false,
+    "declaration": true,
     "esModuleInterop": true
   },
   "include": [