import { isTransformStreamDefaultController } from "https://deno.land/x/deno@v1.0.0/cli/js/web/streams/internals.ts";
Returns
x is TransformStreamDefaultControllerImpl<any, any>
x/deno/cli/js/web/streams/internals.ts>isTransformStreamDefaultController
import { isTransformStreamDefaultController } from "https://deno.land/x/deno@v1.0.0/cli/js/web/streams/internals.ts";