From f51e1d1d66926bd145165bacce09f780a186a974 Mon Sep 17 00:00:00 2001
From: ItsOnlyBinary <ItsOnlyBinary@users.noreply.github.com>
Date: Wed, 21 Aug 2024 15:18:10 +0100
Subject: [PATCH] Make setTopic() remove the topic if newTopic is falsy (#367)

* Make setTopic() remove the topic if newTopic is falsy

* add clearTopic function

* Improve documentation for setTopic
---
 docs/clientapi.md |  5 ++++-
 src/client.js     | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/docs/clientapi.md b/docs/clientapi.md
index 914e01f..9a1eec9 100644
--- a/docs/clientapi.md
+++ b/docs/clientapi.md
@@ -109,7 +109,10 @@ Join a channel, optionally with a key/password.
 Part/leave a channel with an optional parting message.
 
 ##### `.setTopic(channel, newTopic)`
-Set the topic of a channel
+Set the topic of a channel, if newTopic is falsy or only whitespace then `.clearTopic()` will be called.
+
+##### `.clearTopic(channel)`
+Remove the topic of a channel.
 
 ##### `.ctcpRequest(target, type [, paramN])`
 Send a CTCP request to target with any number of parameters.
diff --git a/src/client.js b/src/client.js
index 33ed8b7..41dc30d 100644
--- a/src/client.js
+++ b/src/client.js
@@ -611,9 +611,23 @@ module.exports = class IrcClient extends EventEmitter {
     }
 
     setTopic(channel, newTopic) {
+        if (!newTopic || !newTopic.trim()) {
+            // If newTopic is undefined or empty, remove the existing topic
+            // this check is to prevent unexpectedly requesting the current topic
+            // when trying to clear the topic
+            this.clearTopic(channel);
+            return;
+        }
+
         this.raw('TOPIC', channel, newTopic);
     }
 
+    clearTopic(channel) {
+        // The trailing `:` is required otherwise it would be requesting the topic
+        // and not clearing it
+        this.raw(`TOPIC ${channel} :`);
+    }
+
     ctcpRequest(target, type /*, paramN */) {
         const params = Array.prototype.slice.call(arguments, 1);