import duplexify = require("duplexify"); import { Readable, Writable, Duplex } from "stream"; declare var readable: Readable; declare var writable: Writable; duplexify(writable, readable); duplexify(writable); duplexify(undefined, readable); duplexify.obj(); duplexify.obj(writable); duplexify.obj(writable, readable); duplexify.obj(writable, readable, {}); const d: duplexify.Duplexify = duplexify(); d.setReadable(readable); d.setReadable(); // $ExpectError d.setWritable(writable); d.setWritable(); // $ExpectError d.cork(); d.uncork(); const f: Duplex = d;