From 59df93a6a3202c7f9e9cdbfd4547c66017e35e93 Mon Sep 17 00:00:00 2001
From: Kevin Deng <sxzz@sxzz.moe>
Date: Sun, 30 Nov 2025 07:16:01 +0800
Subject: [PATCH] fix: prevent register twice

---
 src/index.ts        | 10 +++++++++-
 tests/index.test.js | 16 ++++++++++++----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 80b9aa9..7f568e6 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -11,11 +11,15 @@ declare global {
   }
 }
 
+let deregister: (() => void) | undefined
+
 export function init(): () => void {
   if (!module.registerHooks) {
     throw new Error('import-without-cache requires Node.js v20.19.0 or higher.')
   }
 
+  if (deregister) return deregister
+
   const hooks = module.registerHooks({
     resolve(specifier, context, nextResolve) {
       const fromNoCache =
@@ -49,7 +53,11 @@ export function init(): () => void {
       return nextLoad(url, context)
     },
   })
-  return hooks.deregister.bind(hooks)
+
+  return (deregister = () => {
+    hooks.deregister()
+    deregister = undefined
+  })
 }
 
 function cleanupImportAttributes(context: LoadHookContext): void {
diff --git a/tests/index.test.js b/tests/index.test.js
index 4c96d6b..26d3f85 100644
--- a/tests/index.test.js
+++ b/tests/index.test.js
@@ -46,10 +46,7 @@ test('import attributes', async () => {
   deregister()
 
   await assert.rejects(
-    () =>
-      import('./fixtures/mod.js', {
-        with: { cache: 'no' },
-      }),
+    () => import('./fixtures/mod.js', { with: { cache: 'no' } }),
   )
 })
 
@@ -66,3 +63,14 @@ test('no-cache protocol', async () => {
   // @ts-expect-error
   await assert.rejects(() => import('no-cache://./fixtures/mod.js'))
 })
+
+test('register twice', () => {
+  const deregister1 = init()
+  const deregister2 = init()
+  assert.equal(deregister1, deregister2)
+  deregister1()
+
+  const deregister3 = init()
+  assert.notEqual(deregister1, deregister3)
+  deregister3()
+})
-- 
2.51.2