From 1dd958bae45dea4f70848260052c029b1e8a63ac Mon Sep 17 00:00:00 2001
From: Michael Ridgway <191142+mridgway@users.noreply.github.com>
Date: Mon, 8 Apr 2024 17:12:04 -0700
Subject: [PATCH] fix(plugin/babel): bypass directly required plugins or
 presets in babel config

---
 packages/knip/fixtures/plugins/babel/.babelrc.js | 2 ++
 packages/knip/src/plugins/babel/index.ts         | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/knip/fixtures/plugins/babel/.babelrc.js b/packages/knip/fixtures/plugins/babel/.babelrc.js
index 3e2145357..70ad5bce4 100644
--- a/packages/knip/fixtures/plugins/babel/.babelrc.js
+++ b/packages/knip/fixtures/plugins/babel/.babelrc.js
@@ -37,6 +37,8 @@ const config = {
         },
       },
     ],
+    // Simulates a required plugin, should not be added to the unspecified plugins array
+    function myCustomPlugin() {}
   ],
 };
 
diff --git a/packages/knip/src/plugins/babel/index.ts b/packages/knip/src/plugins/babel/index.ts
index ed9e0154f..98942f6db 100644
--- a/packages/knip/src/plugins/babel/index.ts
+++ b/packages/knip/src/plugins/babel/index.ts
@@ -16,7 +16,7 @@ const isEnabled: IsPluginEnabled = ({ dependencies }) => hasDependency(dependenc
 const config = ['babel.config.{json,js,cjs,mjs,cts}', '.babelrc.{json,js,cjs,mjs,cts}', '.babelrc', 'package.json'];
 
 const getName = (value: string | [string, unknown]) =>
-  typeof value === 'string' ? [value] : Array.isArray(value) ? [value[0]] : [];
+  [Array.isArray(value) ? value[0] : value].filter(name => typeof name === 'string');
 
 export const getDependenciesFromConfig = (config: BabelConfigObj): string[] => {
   const presets = config.presets?.flatMap(getName).map(name => resolveName(name, 'preset')) ?? [];