stream: dont wait for next item in take when finished

PR-URL: #47132
Reviewed-By: Robert Nagy <[email protected]>
Reviewed-By: Yagiz Nizipli <[email protected]>
Reviewed-By: Erick Wendel <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Debadree Chatterjee <[email protected]>

Author: rluvaton

lib/internal/streams/operators.js

@@ -409,7 +409,10 @@ function take(number, options = undefined) {
       }
       if (number-- > 0) {
         yield val;
-      } else {
+      }
+
+      // Don't get another item from iterator in case we reached the end
+      if (number <= 0) {
         return;
       }
     }

test/parallel/test-stream-drop-take.js

@@ -4,7 +4,7 @@ const common = require('../common');
 const {
   Readable,
 } = require('stream');
-const { deepStrictEqual, rejects, throws } = require('assert');
+const { deepStrictEqual, rejects, throws, strictEqual } = require('assert');
 
 const { from } = Readable;
 
@@ -49,6 +49,28 @@ const naturals = () => from(async function*() {
   })().then(common.mustCall());
 }
 
+
+// Don't wait for next item in the original stream when already consumed the requested take amount
+{
+  let reached = false;
+  let resolve;
+  const promise = new Promise((res) => resolve = res);
+
+  const stream = from((async function *() {
+    yield 1;
+    await promise;
+    reached = true;
+    yield 2;
+  })());
+
+  stream.take(1)
+    .toArray()
+    .then(common.mustCall(() => {
+      strictEqual(reached, false);
+    }))
+    .finally(() => resolve());
+}
+
 {
   // Coercion
   (async () => {