1 files changed, 4 insertions, 0 deletions
diff --git a/u/fn/callable.ts b/u/fn/callable.ts
index 2749947..a087928 100644
--- a/u/fn/callable.ts
+++ b/u/fn/callable.ts
@@ -13,3 +13,7 @@ export interface SideEffect<T> extends Callable<void, T> {
 export interface Mapper<T, U> extends Callable<U, T> {
   (t: T): U;
 }
+
+export interface BiMapper<T, U, R> extends Callable {
+  (t: T, u: U): R;
+}