Use brand check of .locked in IsReadableStreamLike

src/lib/helpers/stream-like.ts

@@ -63,13 +63,23 @@ interface WritableStreamDefaultWriterLike<W = any> {
 }
 
 export function IsReadableStreamLike(x: unknown): x is ReadableStreamLike {
- return typeIsObject(x) && typeof (x as ReadableStreamLike).getReader === 'function';
-}
-
-export function IsReadableByteStreamLike(x: unknown): x is ReadableByteStreamLike {
- if (!IsReadableStreamLike(x)) {
+ if (!typeIsObject(x)) {
  return false;
  }
+ if (typeof (x as ReadableStreamLike).getReader !== 'function') {
+ return false;
+ }
+ try {
+ // noinspection SuspiciousTypeOfGuard
+ return typeof (x as ReadableStreamLike).locked === 'boolean';
+ } catch {
+ // ReadableStream.prototype.locked may throw if its brand check fails
+ return false;
+ }
+}
+
+export function IsReadableByteStreamLike(x: ReadableStreamLike): x is ReadableByteStreamLike {
+ assert(IsReadableStreamLike(x));
 
  // This brand check only works for unlocked streams.
  // If the stream is locked, getReader() will throw even if "byob" is actually supported.
@@ -85,5 +95,17 @@ export function IsReadableByteStreamLike(x: unknown): x is ReadableByteStreamLik
 }
 
 export function IsWritableStreamLike(x: unknown): x is WritableStreamLike {
- return typeIsObject(x) && typeof (x as WritableStreamLike).getWriter === 'function';
+ if (!typeIsObject(x)) {
+ return false;
+ }
+ if (typeof (x as WritableStreamLike).getWriter !== 'function') {
+ return false;
+ }
+ try {
+ // noinspection SuspiciousTypeOfGuard
+ return typeof (x as WritableStreamLike).locked === 'boolean';
+ } catch {
+ // WritableStream.prototype.locked may throw if its brand check fails
+ return false;
+ }
 }