cluster: return worker reference from disconnect()

Changes disconnect() to return a refererence to the worker.
This will enable method chaining such as

    worker.disconnect().once('disconnect', doThis);

PR-URL: https://github.com/nodejs/node/pull/10019
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/test/parallel/test-cluster-worker-destroy.js b/test/parallel/test-cluster-worker-destroy.js
index c802177530..ca3ac77e7b 100644
--- a/test/parallel/test-cluster-worker-destroy.js
+++ b/test/parallel/test-cluster-worker-destroy.js
@@ -8,6 +8,7 @@
  */
 
 const common = require('../common');
+const assert = require('assert');
 var cluster = require('cluster');
 var worker1, worker2;
 
@@ -26,7 +27,8 @@ if (cluster.isMaster) {
       cluster.worker.destroy();
     });
 
-    cluster.worker.disconnect();
+    const w = cluster.worker.disconnect();
+    assert.strictEqual(w, cluster.worker, 'did not return a reference');
   } else {
     // Call destroy when worker is not disconnected yet
     cluster.worker.destroy();