diff --git a/tools/index.d.ts b/tools/index.d.ts
index 0f9c11ec43..83094445f0 100644
--- a/tools/index.d.ts
+++ b/tools/index.d.ts
@@ -18,9 +18,9 @@ declare global {
     displayName?: string;
   }
 
-  type StringOrRegExp = string | RegExp;
+  type DiscardPattern = string | RegExp;
 
   interface Discards {
-    [packageName: string]: StringOrRegExp[];
+    [packageName: string]: DiscardPattern[];
   }
 }
diff --git a/tools/isobuild/npm-discards.ts b/tools/isobuild/npm-discards.ts
index 33b950a573..7c883fd230 100644
--- a/tools/isobuild/npm-discards.ts
+++ b/tools/isobuild/npm-discards.ts
@@ -76,7 +76,7 @@ function merge(into: Discards, from: Discards): void {
 
 // TODO Improve this. For example we don't currently support wildcard
 // string patterns (just use a RegExp if you need that flexibility).
-function matches(pattern: StringOrRegExp, relPath: string): boolean {
+function matches(pattern: DiscardPattern, relPath: string): boolean {
   if (pattern instanceof RegExp) {
     return pattern.test(relPath);
   }