diff --git a/tools/index.d.ts b/tools/index.d.ts
index 62c834e501..0f9c11ec43 100644
--- a/tools/index.d.ts
+++ b/tools/index.d.ts
@@ -17,4 +17,10 @@ declare global {
     // func-utils.ts makes usage of this feature
     displayName?: string;
   }
+
+  type StringOrRegExp = string | RegExp;
+
+  interface Discards {
+    [packageName: string]: StringOrRegExp[];
+  }
 }
diff --git a/tools/isobuild/npm-discards.ts b/tools/isobuild/npm-discards.ts
index dbb6d49111..6391eb082a 100644
--- a/tools/isobuild/npm-discards.ts
+++ b/tools/isobuild/npm-discards.ts
@@ -2,12 +2,6 @@ import * as files from "../fs/files";
 
 const hasOwn = Object.prototype.hasOwnProperty;
 
-type StringOrRegExp = string | RegExp;
-
-interface Discards {
-  [packageName: string]: StringOrRegExp[];
-}
-
 // This class encapsulates a structured specification of files and
 // directories that should be stripped from the node_modules directories
 // of Meteor packages during `meteor build`, as requested by calling