only including needed core-js function

src/main.ts

@@ -1,2 +1,2 @@
-require('core-js');
+import 'core-js/es/object/entries';
 module.exports = require('./Player.js').Player;

tsconfig.json

@@ -1,7 +1,7 @@
 {
    "compilerOptions": {
       "target": "es5",
-      "lib": ["es2017", "dom"],
+      "lib": ["es2017.object", "dom"],
       "module": "commonjs",
       "moduleResolution": "node",
       "baseUrl": "./src",