fix: consume iterable as many as call in takeUntil

marpple · Dec 2, 2021 · 04a1937 · 04a1937
1 parent f061567
commit 04a1937
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Showing 2 changed files with 19 additions and 0 deletions.
diff --git a/src/Lazy/takeUntil.ts b/src/Lazy/takeUntil.ts
@@ -30,6 +30,10 @@ function asyncSequential<A, B>(
       return this;
     },
     async next(_concurrent) {
+      if (end) {
+        return { done: true, value: undefined };
+      }
+
       const { done, value } = await iterator.next(_concurrent);
       if (done || end) {
         return { done: true, value: undefined };

diff --git a/test/Lazy/takeUntil.spec.ts b/test/Lazy/takeUntil.spec.ts
@@ -3,6 +3,7 @@ import {
   delay,
   filter,
   map,
+  peek,
   pipe,
   range,
   takeUntil,
@@ -95,6 +96,20 @@ describe("takeUntil", function () {
       expect(res).toEqual([12, 14]);
     });
 
+    it("should be able to take the element", async function () {
+      const fn = jest.fn();
+      const res = await pipe(
+        toAsync([3, 3, 1, 0, 0]),
+        peek(fn),
+        map((a) => delay(100, a)),
+        takeUntil((a) => a < 3),
+        toArray,
+      );
+
+      expect(fn).toHaveBeenCalledTimes(3);
+      expect(res).toEqual([3, 3, 1]);
+    }, 350);
+
     it("should be able to take the element until the callback result is truthy concurrently", async function () {
       const res = await pipe(
         toAsync(range(1, 20)),