[Streams API] Add writable stream attributes
[WebKit-https.git] / Source / WebCore / Modules / streams / WritableStreamInternals.js
index 45da2c3..9151fed 100644 (file)
 // @optional=STREAMS_API
 // @internals
 
+function isWritableStream(stream)
+{
+    "use strict";
+
+    return @isObject(stream) && !!stream.@underlyingSink;
+}
+
 function syncWritableStreamStateWithQueue(stream)
 {
     "use strict";