1 files changed, 22 insertions, 0 deletions
diff --git a/u/fn/callable.ts b/u/fn/callable.ts
new file mode 100644
index 0000000..fc6ea81
--- /dev/null
+++ b/u/fn/callable.ts
@@ -0,0 +1,22 @@
+// deno-lint-ignore no-explicit-any
+export interface Callable<T = any, ArgT = any> {
+  (...args: Array<ArgT>): T;
+}
+
+export interface Supplier<T> extends Callable<T, undefined> {
+  (): 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;
+}
+
+export interface SideEffect<T> extends Mapper<T, void> {
+}
+
+export interface BiSideEffect<T, U> extends BiMapper<T, U, void> {
+}