From dfdadc7547e3b026da161731d47b0935c477dea2 Mon Sep 17 00:00:00 2001
From: Seth Falco <seth@falco.fun>
Date: Wed, 27 Sep 2023 15:53:00 +0100
Subject: [PATCH] fix: warn and do not crash on null plugin

---
 lib/svgo.js | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/lib/svgo.js b/lib/svgo.js
index 8c5ca130f..6dba24523 100644
--- a/lib/svgo.js
+++ b/lib/svgo.js
@@ -64,13 +64,22 @@ const optimize = (input, config) => {
   for (let i = 0; i < maxPassCount; i += 1) {
     info.multipassCount = i;
     const ast = parseSvg(input, config.path);
+    /** @type {unknown[]|unknown} */
     const plugins = config.plugins || ['preset-default'];
-    if (Array.isArray(plugins) === false) {
+    if (!Array.isArray(plugins)) {
       throw Error(
-        "Invalid plugins list. Provided 'plugins' in config should be an array."
+        'malformed config, `plugins` property must be an array.\nSee more info here: https://github.com/svg/svgo#configuration'
+      );
+    }
+    const resolvedPlugins = plugins
+      .filter((plugin) => plugin != null)
+      .map(resolvePluginConfig);
+
+    if (resolvedPlugins.length < plugins.length) {
+      console.warn(
+        'Warning: plugins list includes null or undefined elements, these will be ignored.'
       );
     }
-    const resolvedPlugins = plugins.map(resolvePluginConfig);
     const globalOverrides = {};
     if (config.floatPrecision != null) {
       globalOverrides.floatPrecision = config.floatPrecision;