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import { asyncNullishChain, nullishChain } from "./nullishChain.ts";import { assertEquals } from "testing/asserts.ts";
Deno.test("nullish chain", () => {  const numChain = nullishChain(    (n: number) => (n === 1 ? n : null),    (n) => (n === 2 ? n : undefined),    (n) => (n === 3 ? n : null),  );
  assertEquals(numChain(1), 1);  assertEquals(numChain(2), 2);  assertEquals(numChain(3), 3);  assertEquals(numChain(4), undefined);
  // @ts-expect-error  // prettier-ignore  nullishChain((_n: number) => 0, (_n: string) => 0);
  // @ts-expect-error  const _str: string = nullishChain(() => 2)();
  const _empty = nullishChain();});
Deno.test("async nullish chain", async () => {  const chain = asyncNullishChain(    (n: number) => {      if (n === 1) return "foo";    },    async (n) => {      if (n === 2) return "bar";    },    (n) =>      new Promise<string | null>((res) =>        setTimeout(() => res(n === 3 ? "baz" : null), 100)      ),  );
  assertEquals(await chain(1), "foo");  assertEquals(await chain(2), "bar");  assertEquals(await chain(3), "baz");  assertEquals(await chain(4), undefined);});