fix(cluster): reorder defaults arguments to prioritize user options (#889)

Author: jstewmon

lib/cluster/index.ts

@@ -68,6 +68,7 @@ class Cluster extends EventEmitter {
 
     this.startupNodes = startupNodes
     this.options = defaults(this.options, options, DEFAULT_CLUSTER_OPTIONS)
+    this.options = defaults({}, options, DEFAULT_CLUSTER_OPTIONS, this.options)
 
     // validate options
     if (typeof this.options.scaleReads !== 'function' &&

test/unit/cluster.js

@@ -15,11 +15,16 @@ describe('cluster', function () {
   it('should support frozen options', function () {
     var options = Object.freeze({ maxRedirections: 1000 });
     var cluster = new Cluster([{ port: 7777 }], options);
-    expect(cluster.options).to.have.property('showFriendlyErrorStack', false);
+    expect(cluster.options).to.have.property('maxRedirections', 1000);
     expect(cluster.options).to.have.property('showFriendlyErrorStack', false);
     expect(cluster.options).to.have.property('scaleReads', 'master');
   });
 
+  it('should allow overriding Commander options', function () {
+    const cluster = new Cluster([{ port: 7777 }], {showFriendlyErrorStack: true});
+    expect(cluster.options).to.have.property('showFriendlyErrorStack', true);
+  })
+
   it('throws when scaleReads is invalid', function () {
     expect(function () {
       new Cluster([{}], { scaleReads: 'invalid' });