streams: remove unnecessary check

lib/internal/webstreams/util.js

@@ -54,12 +54,11 @@ const AsyncIterator = {
 
 function extractHighWaterMark(value, defaultHWM) {
   if (value === undefined) return defaultHWM;
-  value = +value;
-  if (typeof value !== 'number' ||
-      NumberIsNaN(value) ||
-      value < 0)
+  const coercedValue = +value;
+  if (NumberIsNaN(coercedValue) ||
+      coercedValue < 0)
     throw new ERR_INVALID_ARG_VALUE.RangeError('strategy.highWaterMark', value);
-  return value;
+  return coercedValue;
 }
 
 function extractSizeAlgorithm(size) {
@@ -151,13 +150,13 @@ function peekQueueValue(controller) {
 function enqueueValueWithSize(controller, value, size) {
   assert(controller[kState].queue !== undefined);
   assert(controller[kState].queueTotalSize !== undefined);
-  size = +size;
-  if (typeof size !== 'number' ||
-      size < 0 ||
-      NumberIsNaN(size) ||
-      size === Infinity) {
+  const coercedSize = +size;
+  if (NumberIsNaN(coercedSize) ||
+      coercedSize < 0 ||
+      coercedSize === Infinity) {
     throw new ERR_INVALID_ARG_VALUE.RangeError('size', size);
   }
+  size = coercedSize;
   ArrayPrototypePush(controller[kState].queue, { value, size });
   controller[kState].queueTotalSize += size;
 }