stream: truncate fractional limits in take() and drop()

toIntegerOrInfinity() coerced the limit with Number() but never
truncated it, so a fractional limit such as 1.5 made take() yield one
chunk too many and drop() skip one chunk too many. A negative fraction
in (-1, 0) also threw ERR_OUT_OF_RANGE, although ToIntegerOrInfinity()
maps it to -0, which is a valid limit.

Truncate the value toward zero before the range check so the results
match Iterator.prototype.take() and Iterator.prototype.drop().

Signed-off-by: koreahghg <koreahghg@gmail.com>
Assisted-by: Claude Code

Author: koreahghg

lib/internal/streams/operators.js

@@ -4,6 +4,7 @@ const {
   ArrayPrototypePush,
   Boolean,
   MathFloor,
+  MathTrunc,
   Number,
   NumberIsNaN,
   Promise,
@@ -314,10 +315,11 @@ function toIntegerOrInfinity(number) {
   if (NumberIsNaN(number)) {
     return 0;
   }
-  if (number < 0) {
+  const integer = MathTrunc(number);
+  if (integer < 0) {
     throw new ERR_OUT_OF_RANGE('number', '>= 0', number);
   }
-  return number;
+  return integer;
 }
 
 function drop(number, options = undefined) {

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

@@ -81,6 +81,18 @@ const naturals = () => from(async function*() {
   })().then(common.mustCall());
 }
 
+{
+  // Fractional limits are truncated toward zero
+  (async () => {
+    assert.deepStrictEqual(await from([1, 2, 3, 4]).take(1.5).toArray(), [1]);
+    assert.deepStrictEqual(await from([1, 2, 3, 4]).drop(1.5).toArray(), [2, 3, 4]);
+    assert.deepStrictEqual(await from([1, 2, 3, 4]).take(0.5).toArray(), []);
+    assert.deepStrictEqual(await from([1, 2, 3, 4]).drop(0.5).toArray(), [1, 2, 3, 4]);
+    assert.deepStrictEqual(await from([1, 2]).take(-0.5).toArray(), []);
+    assert.deepStrictEqual(await from([1, 2]).drop(-0.5).toArray(), [1, 2]);
+  })().then(common.mustCall());
+}
+
 {
   // Support for AbortSignal
   const ac = new AbortController();
@@ -108,6 +120,7 @@ const naturals = () => from(async function*() {
   // Error cases
   const invalidArgs = [
     -1,
+    -1.5,
     -Infinity,
     -40,
   ];