npm and error messages

node_modules/core-js/modules/_is-array-iter.js

@@ -0,0 +1,8 @@
+// check on default Array iterator
+var Iterators = require('./_iterators');
+var ITERATOR = require('./_wks')('iterator');
+var ArrayProto = Array.prototype;
+
+module.exports = function (it) {
+  return it !== undefined && (Iterators.Array === it || ArrayProto[ITERATOR] === it);
+};