From d0f5b70b1dfb74b432cf294ed2d5c180845c65c3 Mon Sep 17 00:00:00 2001
From: aje <andrew@ellerton.net>
Date: Tue, 7 Mar 2023 13:40:21 +0800
Subject: [PATCH] Idempotent logging on browser

Certain modules do not exist in a browser environment.
In that environment, file-based appenders are effectively
disabled by this commit, without modifying the source directly.
---
 lib/appenders/ignoreBrowser.js |  0
 lib/clusteringBrowser.js       | 19 +++++++++++++++++++
 package.json                   |  8 +++++++-
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 lib/appenders/ignoreBrowser.js
 create mode 100644 lib/clusteringBrowser.js

diff --git a/lib/appenders/ignoreBrowser.js b/lib/appenders/ignoreBrowser.js
new file mode 100644
index 0000000..e69de29
diff --git a/lib/clusteringBrowser.js b/lib/clusteringBrowser.js
new file mode 100644
index 0000000..fcae301
--- /dev/null
+++ b/lib/clusteringBrowser.js
@@ -0,0 +1,19 @@
+/* istanbul ignore file */
+// This is used in browsers only and is designed to allow the rest of
+// log4js to continue as if `clustering.js` is in use.
+const isMaster = () => true;
+
+const listeners = [];
+
+const sendToListeners = (logEvent) => {
+  listeners.forEach((l) => l(logEvent));
+};
+
+module.exports = {
+  onlyOnMaster: (fn, notMaster) => (isMaster() ? fn() : notMaster),
+  isMaster,
+  send: sendToListeners,
+  onMessage: (listener) => {
+    listeners.push(listener);
+  },
+};
diff --git a/package.json b/package.json
index abe28e8..14a861c 100644
--- a/package.json
+++ b/package.json
@@ -73,7 +73,13 @@
     "typescript": "^4.9.5"
   },
   "browser": {
-    "os": false
+    "os": false,
+    "streamroller": false,
+    "./lib/clustering.js": "./lib/clusteringBrowser.js",
+    "./lib/appenders/dateFile.js": "./lib/appenders/ignoreBrowser.js",
+    "./lib/appenders/file.js": "./lib/appenders/ignoreBrowser.js",
+    "./lib/appenders/fileSync.js": "./lib/appenders/ignoreBrowser.js",
+    "./lib/appenders/multiFile.js": "./lib/appenders/ignoreBrowser.js"
   },
   "prettier": {
     "trailingComma": "es5",