Flow doesn't that map.has means that I can use map.get

packages/babel-preset-env/src/index.js

@@ -2,10 +2,7 @@
 
 import { logPluginOrPolyfill } from "./debug";
 import getOptionSpecificExcludesFor from "./get-option-specific-excludes";
-import filterItems, {
-  removeUnnecessaryItems,
-  isPluginRequired,
-} from "./filter-items";
+import filterItems, { removeUnnecessaryItems } from "./filter-items";
 import moduleTransformations from "./module-transformations";
 import normalizeOptions from "./normalize-options";
 import pluginList from "../data/plugins.json";