npm and error messages

node_modules/core-js/modules/es7.reflect.delete-metadata.js

@@ -0,0 +1,15 @@
+var metadata = require('./_metadata');
+var anObject = require('./_an-object');
+var toMetaKey = metadata.key;
+var getOrCreateMetadataMap = metadata.map;
+var store = metadata.store;
+
+metadata.exp({ deleteMetadata: function deleteMetadata(metadataKey, target /* , targetKey */) {
+  var targetKey = arguments.length < 3 ? undefined : toMetaKey(arguments[2]);
+  var metadataMap = getOrCreateMetadataMap(anObject(target), targetKey, false);
+  if (metadataMap === undefined || !metadataMap['delete'](metadataKey)) return false;
+  if (metadataMap.size) return true;
+  var targetMetadata = store.get(target);
+  targetMetadata['delete'](targetKey);
+  return !!targetMetadata.size || store['delete'](target);
+} });