diff --git a/packages/babel-core/src/transformation/file/file.js b/packages/babel-core/src/transformation/file/file.js
index 79ef660161..2c026fd2c5 100644
--- a/packages/babel-core/src/transformation/file/file.js
+++ b/packages/babel-core/src/transformation/file/file.js
@@ -56,6 +56,10 @@ export default class File {
     return this._map.get(key);
   }
 
+  has(key: mixed): boolean {
+    return this._map.has(key);
+  }
+
   getModuleName(): ?string {
     const opts = this.opts;
     if (!opts.moduleIds) {