cluster: remove bind() and self

This commit removes the use of self and bind() from the cluster
module in favor of arrow functions.
PR-URL: #7710
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Minwoo Jung <jmwsoft@gmail.com>

Author: cjihrig

lib/cluster.js

@@ -127,31 +127,29 @@ function RoundRobinHandle(key, address, port, addressType, backlog, fd) {
 else
 this.server.listen(address);// UNIX socket path.
 
-varself=this;
-this.server.once('listening',function(){
-self.handle=self.server._handle;
-self.handle.onconnection=self.distribute.bind(self);
-self.server._handle=null;
-self.server=null;
+this.server.once('listening',()=>{
+this.handle=this.server._handle;
+this.handle.onconnection=(err,handle)=>this.distribute(err,handle);
+this.server._handle=null;
+this.server=null;
 });
 }
 
 RoundRobinHandle.prototype.add=function(worker,send){
 assert(worker.idinthis.all===false);
 this.all[worker.id]=worker;
 
-varself=this;
-functiondone(){
-if(self.handle.getsockname){
+constdone=()=>{
+if(this.handle.getsockname){
 varout={};
-self.handle.getsockname(out);
+this.handle.getsockname(out);
 // TODO(bnoordhuis) Check err.
 send(null,{sockname: out},null);
 }else{
 send(null,null,null);// UNIX socket.
 }
-self.handoff(worker);// In case there are connections pending.
-}
+this.handoff(worker);// In case there are connections pending.
+};
 
 if(this.server===null)returndone();
 // Still busy binding.
@@ -193,13 +191,13 @@ RoundRobinHandle.prototype.handoff = function(worker) {
 return;
 }
 varmessage={act: 'newconn',key: this.key};
-varself=this;
-sendHelper(worker.process,message,handle,function(reply){
+
+sendHelper(worker.process,message,handle,(reply)=>{
 if(reply.accepted)
 handle.close();
 else
-self.distribute(0,handle);// Worker is shutting down. Send to another.
-self.handoff(worker);
+this.distribute(0,handle);// Worker is shutting down. Send to another.
+this.handoff(worker);
 });
 };
 
@@ -414,7 +412,7 @@ function masterInit() {
 cluster.disconnect=function(cb){
 varworkers=Object.keys(cluster.workers);
 if(workers.length===0){
-process.nextTick(intercom.emit.bind(intercom,'disconnect'));
+process.nextTick(()=>intercom.emit('disconnect'));
 }else{
 for(varkeyinworkers){
 key=workers[key];
@@ -436,7 +434,7 @@ function masterInit() {
 signo=signo||'SIGTERM';
 varproc=this.process;
 if(this.isConnected()){
-this.once('disconnect',proc.kill.bind(proc,signo));
+this.once('disconnect',()=>proc.kill(signo));
 this.disconnect();
 return;
 }