From c96a762ffc45cd51809b3608eb22e9a2f22eff0a Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Fri, 29 Sep 2023 00:39:29 +0300
Subject: [PATCH] Split long if-elseif into functions

---
 tinyraft.js | 158 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 93 insertions(+), 65 deletions(-)

diff --git a/tinyraft.js b/tinyraft.js
index dbd8f6c..a59aaae 100644
--- a/tinyraft.js
+++ b/tinyraft.js
@@ -125,83 +125,111 @@ class TinyRaft extends EventEmitter
     {
         if (msg.type == VOTE_REQUEST)
         {
-            if (msg.term > this.term && msg.leader)
+            this.onReceiveVoteRequest(from, msg);
+        }
+        else if (msg.type == VOTE)
+        {
+            this.onReceiveVote(from, msg);
+        }
+        else if (msg.type == PING)
+        {
+            this.onReceivePing(from, msg);
+        }
+        else if (msg.type == PONG)
+        {
+            this.onReceivePong(from, msg);
+        }
+    }
+
+    onReceiveVoteRequest(from, msg)
+    {
+        if (msg.term > this.term && msg.leader)
+        {
+            this.leader = msg.leader;
+            this.term = msg.term;
+            this.state = CANDIDATE;
+            this._nextTerm(this.heartbeatTimeout*2 + this.electionTimeout);
+            this.emit('change', { state: this.state, term: this.term, leader: this.leader });
+        }
+        this.send(from, { type: VOTE, term: this.term, leader: this.leader });
+    }
+
+    onReceiveVote(from, msg)
+    {
+        if (msg.term != this.term)
+        {
+            return;
+        }
+        this.voted++;
+        this.votes[msg.leader] = this.votes[msg.leader] || [];
+        this.votes[msg.leader].push(from);
+        const n = this.votes[msg.leader].length;
+        if (n == 1 + (0 | this.nodes.length/2))
+        {
+            if (msg.leader == this.nodeId)
             {
                 this.leader = msg.leader;
-                this.term = msg.term;
-                this.state = CANDIDATE;
-                this._nextTerm(this.heartbeatTimeout*2 + this.electionTimeout);
-                this.emit('change', { state: this.state, term: this.term, leader: this.leader });
-            }
-            this.send(from, { type: VOTE, term: this.term, leader: this.leader });
-        }
-        else if (msg.type == VOTE && msg.term == this.term)
-        {
-            this.voted++;
-            this.votes[msg.leader] = this.votes[msg.leader] || [];
-            this.votes[msg.leader].push(from);
-            const n = this.votes[msg.leader].length;
-            if (n == 1 + (0 | this.nodes.length/2))
-            {
-                if (msg.leader == this.nodeId)
-                {
-                    this.leader = msg.leader;
-                    this.state = LEADER;
-                    this._nextTerm(this.leadershipTimeout > 0 ? this.leadershipTimeout : -1);
-                    this.followers = this.votes[this.nodeId];
-                    for (const follower of this.followers)
-                    {
-                        if (follower != this.nodeId)
-                        {
-                            // Send a heartbeat to confirm leadership
-                            this.send(follower, { type: PING, term: this.term });
-                        }
-                    }
-                    this.emit('change', { state: this.state, term: this.term, leader: this.nodeId, followers: this.votes[this.nodeId] });
-                }
-                else
-                {
-                    this._nextTerm(0);
-                }
-            }
-            else if (n > this.nodes.length/2 && this.state == LEADER && msg.leader == this.nodeId)
-            {
+                this.state = LEADER;
+                this._nextTerm(this.leadershipTimeout > 0 ? this.leadershipTimeout : -1);
                 this.followers = this.votes[this.nodeId];
-                // Send a heartbeat to confirm leadership
-                this.send(from, { type: PING, term: this.term });
+                for (const follower of this.followers)
+                {
+                    if (follower != this.nodeId)
+                    {
+                        // Send a heartbeat to confirm leadership
+                        this.send(follower, { type: PING, term: this.term });
+                    }
+                }
                 this.emit('change', { state: this.state, term: this.term, leader: this.nodeId, followers: this.votes[this.nodeId] });
             }
-            else if (this._isVotingFailed())
+            else
             {
                 this._nextTerm(0);
             }
         }
-        else if (msg.type == PING)
+        else if (n > this.nodes.length/2 && this.state == LEADER && msg.leader == this.nodeId)
         {
-            if (this.state == CANDIDATE && this.term == msg.term && from == this.leader)
-            {
-                this.state = FOLLOWER;
-                this.emit('change', { state: this.state, term: this.term, leader: this.nodeId });
-            }
-            if (this.state == FOLLOWER && from == this.leader)
-            {
-                this.markAlive();
-            }
-            if (this.leadershipTimeout > 0)
-            {
-                this.send(from, { type: PONG, term: this.term, leader: this.leader });
-            }
+            this.followers = this.votes[this.nodeId];
+            // Send a heartbeat to confirm leadership
+            this.send(from, { type: PING, term: this.term });
+            this.emit('change', { state: this.state, term: this.term, leader: this.nodeId, followers: this.votes[this.nodeId] });
         }
-        else if (msg.type == PONG && this.state == LEADER)
+        else if (this._isVotingFailed())
         {
-            if (msg.leader != this.nodeId)
-            {
-                this.start();
-            }
-            else
-            {
-                this._nextTerm(this.leadershipTimeout > 0 ? this.leadershipTimeout : -1);
-            }
+            this._nextTerm(0);
+        }
+    }
+
+    onReceivePing(from, msg)
+    {
+        if (this.state == CANDIDATE && this.term == msg.term && from == this.leader)
+        {
+            this.state = FOLLOWER;
+            this.emit('change', { state: this.state, term: this.term, leader: this.nodeId });
+        }
+        if (this.state == FOLLOWER && from == this.leader)
+        {
+            this.markAlive();
+        }
+        if (this.leadershipTimeout > 0)
+        {
+            this.send(from, { type: PONG, term: this.term, leader: this.leader });
+        }
+    }
+
+    onReceivePong(from, msg)
+    {
+        if (this.state != LEADER)
+        {
+            return;
+        }
+        if (msg.leader != this.nodeId)
+        {
+            this.start();
+        }
+        else
+        {
+            this._nextTerm(this.leadershipTimeout > 0 ? this.leadershipTimeout : -1);
         }
     }