feat(api): add async types

packages/api/package.json

@@ -81,6 +81,9 @@
 		"./assoc": {
 			"default": "./assoc.js"
 		},
+		"./async": {
+			"default": "./async.js"
+		},
 		"./bind": {
 			"default": "./bind.js"
 		},

packages/api/src/async.ts

@@ -0,0 +1,24 @@
+import type { Fn, Fn0, Fn2 } from "./fn.js";
+
+export type MaybePromise<T> = T | Promise<T>;
+
+export type MaybeAsyncIterable<T> = Iterable<T> | AsyncIterable<T>;
+
+export type MaybeAsyncGenerator<T> =
+	| IterableIterator<T>
+	| AsyncIterableIterator<T>;
+
+export type AsyncPredicate<T> = Fn<T, Promise<boolean>>;
+
+export type AsyncPredicate2<T> = Fn2<T, T, Promise<boolean>>;
+
+export type AsyncStatefulPredicate<T> = Fn0<AsyncPredicate<T>>;
+
+export type AsyncStatefulPredicate2<T> = Fn0<AsyncPredicate2<T>>;
+
+/**
+ * Async version of {@link identity}.
+ *
+ * @param x
+ */
+export const asyncIdentity = async <T>(x: T) => x;

packages/api/src/index.ts

@@ -1,4 +1,5 @@
 export * from "./assoc.js";
+export * from "./async.js";
 export * from "./bind.js";
 export * from "./buffered.js";
 export * from "./clear.js";