From 27ccf1e72b1cac4c13060954f0da78cc381c6b7a Mon Sep 17 00:00:00 2001
From: Tim Fish <tim@timfish.uk>
Date: Wed, 20 May 2026 23:53:07 +0100
Subject: [PATCH 1/2] feat: Support matching Regex `filepath`

---
 index.d.ts           |  2 +-
 lib/matcher.js       |  2 +-
 tests/tests.test.mjs | 13 +++++++++++++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index eee2794..f9c9cc8 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -73,7 +73,7 @@ export interface ModuleMatcher {
     /**
      * The path of the file you want to match from the module root
      */
-    filePath: string;
+    filePath: string | RegExp;
 }
 
 /**
diff --git a/lib/matcher.js b/lib/matcher.js
index 0d5bad5..2971870 100644
--- a/lib/matcher.js
+++ b/lib/matcher.js
@@ -61,7 +61,7 @@ class InstrumentationMatcher {
 
     const configs = this.#configs.filter(({ module: mod }) =>
       mod.name === moduleName &&
-      mod.filePath === filePath &&
+      (typeof mod.filePath === 'string' ? mod.filePath === filePath : mod.filePath.test(filePath)) &&
       semifies(version, mod.versionRange)
     )
 
diff --git a/tests/tests.test.mjs b/tests/tests.test.mjs
index 225bcb8..bff6e1f 100644
--- a/tests/tests.test.mjs
+++ b/tests/tests.test.mjs
@@ -13,6 +13,7 @@ const TEST_MODULE_NAME = 'undici'
 const TEST_MODULE_VERSION = '0.0.1'
 const TEST_MODULE_PATH = 'index.mjs'
 const WINDOWS_MODULE_PATH = 'lib/index.mjs'
+const WINDOWS_MODULE_REGEX = /lib\/index\.m?js/
 
 function runTest (testName, configs, { mjs = false, filePath = TEST_MODULE_PATH, dcModule, customTransforms = {} } = {}) {
   const ext = mjs ? 'mjs' : 'js'
@@ -309,6 +310,18 @@ describe('windows_path', () => {
   })
 })
 
+describe('windows_path_regex', () => {
+  test('instruments with windows-style file path matching regex', () => {
+    runTest('windows_path', [
+      {
+        channelName: 'fetch_decl',
+        module: { name: TEST_MODULE_NAME, versionRange: '>=0.0.1', filePath: WINDOWS_MODULE_REGEX },
+        functionQuery: { functionName: 'fetch', kind: 'Async' },
+      },
+    ], { filePath: 'lib\\index.mjs' })
+  })
+})
+
 describe('export_alias_mjs', () => {
   test('instruments async function declaration via export alias (mjs)', () => {
     runTest('export_alias_mjs', [

From ec34c61e1ffe93beec15f187374764fe83b87fb3 Mon Sep 17 00:00:00 2001
From: Tim Fish <tim@timfish.uk>
Date: Thu, 21 May 2026 10:26:51 +0100
Subject: [PATCH 2/2] Add change to readme

---
 README.md | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 0c7c915..5fa35cf 100644
--- a/README.md
+++ b/README.md
@@ -123,9 +123,15 @@ type FunctionQuery =
 
 ```ts
 type ModuleMatcher = {
-    name: string; // Module name
-    versionRange: string; // Matching semver range
-    filePath: string; // Relative Unix-style path to the file from the module root (e.g. "lib/index.js")
+    /** Module name */
+    name: string; 
+    /** Matching semver range */
+    versionRange: string;
+    /** 
+     * Relative Unix-style path to the file from the module root (e.g. "lib/index.js") 
+     * Or a regular expression to test against the Unix-style path.
+     */
+    filePath: string | RegExp;
 };
 ```