So siehts ganz gut aus !

node_modules/core-js/library/modules/es6.date.to-iso-string.js

@@ -0,0 +1,8 @@
+// 20.3.4.36 / 15.9.5.43 Date.prototype.toISOString()
+var $export = require('./_export');
+var toISOString = require('./_date-to-iso-string');
+
+// PhantomJS / old WebKit has a broken implementations
+$export($export.P + $export.F * (Date.prototype.toISOString !== toISOString), 'Date', {
+  toISOString: toISOString
+});