diff --git a/pages/docs/mutation.en-US.mdx b/pages/docs/mutation.en-US.mdx
index 2f962d30..72b3c2ed 100644
--- a/pages/docs/mutation.en-US.mdx
+++ b/pages/docs/mutation.en-US.mdx
@@ -130,21 +130,17 @@ Also, this hook doesn’t share states with other `useSWRMutation` hooks.
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// Fetcher implementation.
-// The extra argument will be passed via the `arg` property of the 2nd parameter.
-// In the example below, `arg` will be `'my_token'`
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // A useSWR + mutate like API, but it will not start the request automatically.
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // Fetcher implementation.
+      // The extra argument will be passed via the `arg` property of the 2nd parameter.
+      // In the example below, `arg` will be `'my_token'`
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // Trigger `updateUser` with a specific argument.
@@ -181,22 +177,18 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string }}) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* options */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* options */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // error handling
         }
diff --git a/pages/docs/mutation.es-ES.mdx b/pages/docs/mutation.es-ES.mdx
index 4d6da833..6a182690 100644
--- a/pages/docs/mutation.es-ES.mdx
+++ b/pages/docs/mutation.es-ES.mdx
@@ -131,21 +131,17 @@ Also, this hook doesn’t share states with other `useSWRMutation` hooks.
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// Fetcher implementation.
-// The extra argument will be passed via the `arg` property of the 2nd parameter.
-// In the example below, `arg` will be `'my_token'`
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // A useSWR + mutate like API, but it will not start the request automatically.
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // Fetcher implementation.
+      // The extra argument will be passed via the `arg` property of the 2nd parameter.
+      // In the example below, `arg` will be `'my_token'`
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // Trigger `updateUser` with a specific argument.
@@ -182,22 +178,18 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string } }) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* options */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* options */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // error handling
         }
diff --git a/pages/docs/mutation.fr-FR.mdx b/pages/docs/mutation.fr-FR.mdx
index fbde09f0..54efc0dc 100644
--- a/pages/docs/mutation.fr-FR.mdx
+++ b/pages/docs/mutation.fr-FR.mdx
@@ -128,21 +128,17 @@ Aussi, ce hook ne partage pas les états avec d'autres hooks `useSWRMutation`.
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// Implementation de Fetcher.
-// L'argument supplémentaire sera passé via la propriété `arg` du 2ème paramètre.
-// Dans l'exemple ci-dessous, `arg` sera `'my_token'`
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // Une API comme `useSWR` + mutate, mais elle ne déclenchera pas la requête automatiquement.
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // Implementation de Fetcher.
+      // L'argument supplémentaire sera passé via la propriété `arg` du 2ème paramètre.
+      // Dans l'exemple ci-dessous, `arg` sera `'my_token'`
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // Déclange `updateUser` avec un argument spécifique.
@@ -179,15 +175,11 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string }}) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* options */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
@@ -200,7 +192,7 @@ function App() {
         }
       }}
     >
-      Creation d'utilisateur
+      Create User
     </button>
   )
 }
diff --git a/pages/docs/mutation.ja.mdx b/pages/docs/mutation.ja.mdx
index 49e97353..79010cee 100644
--- a/pages/docs/mutation.ja.mdx
+++ b/pages/docs/mutation.ja.mdx
@@ -132,21 +132,17 @@ try {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// フェッチャーの実装
-// 追加の引数は第二引数の `arg` プロパティとして渡されます
-// 下記の例では、`arg` は `'my_token'` となります
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // useSWR と mutate を組み合わせたような API ですが、リクエストを自動的に開始しません
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // フェッチャーの実装
+      // 追加の引数は第二引数の `arg` プロパティとして渡されます
+      // 下記の例では、`arg` は `'my_token'` となります
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // `updateUser` を指定した引数と一緒に実行します
@@ -183,22 +179,18 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string } }) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* options */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* options */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // エラーハンドリング
         }
diff --git a/pages/docs/mutation.ko.mdx b/pages/docs/mutation.ko.mdx
index 7206cea0..528beb85 100644
--- a/pages/docs/mutation.ko.mdx
+++ b/pages/docs/mutation.ko.mdx
@@ -130,21 +130,17 @@ SWR은 remote mutation을 위한 hook으로 `useSWRMutation`을 제공합니다.
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// Fetcher 구현.
-// 추가 인수는 두 번째 매개변수의 `arg` 속성을 통해 전달됩니다.
-// 아래 예제에서 `arg`는 `'my_token'`이 됩니다.
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // useSWR + mutate 같은 API를 사용하지만, 자동으로 요청을 시작하지는 않습니다.
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // Fetcher 구현.
+      // 추가 인수는 두 번째 매개변수의 `arg` 속성을 통해 전달됩니다.
+      // 아래 예제에서 `arg`는 `'my_token'`이 됩니다.
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // 특정 인수를 사용하여 `updateUser`를 트리거 합니다.
@@ -181,22 +177,18 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string } }) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* options */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* options */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // 에러 핸들링
         }
diff --git a/pages/docs/mutation.pt-BR.mdx b/pages/docs/mutation.pt-BR.mdx
index bfa9b8ee..8bb32173 100644
--- a/pages/docs/mutation.pt-BR.mdx
+++ b/pages/docs/mutation.pt-BR.mdx
@@ -128,26 +128,22 @@ Também, esse hook não compartilha estado com outros hooks `useSWRMutation`.
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// Implementação do fetcher.
-// O argumento extra será passado via propriedade `arg` do segundo parâmetro.
-// No exemplo abaixo, `arg` será `my_token`
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // Uma API como useSWR + mutate, mas não irá começar o request automaticamente.
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // Implementação do fetcher.
+      // O argumento extra será passado via propriedade `arg` do segundo parâmetro.
+      // No exemplo abaixo, `arg` será `my_token`
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // Dispara `updateUser` com um argumento específico
     trigger('my_token')
-  }}>Atualizar usuário</button>
+  }}>Update User</button>
 }
 ```
 
@@ -179,28 +175,24 @@ function Profile() {
 ```jsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string } }) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* opções */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* opções */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // lidando com erros
         }
       }}
     >
-      Criar Usuário
+      Create User
     </button>
   )
 }
diff --git a/pages/docs/mutation.ru.mdx b/pages/docs/mutation.ru.mdx
index 96593e31..c088894a 100644
--- a/pages/docs/mutation.ru.mdx
+++ b/pages/docs/mutation.ru.mdx
@@ -131,21 +131,17 @@ SWR также предоставляет `useSWRMutation` в качестве 
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// Реализация fetcher-а.
-// Дополнительный аргумент будет передан через свойство `arg` второго параметра.
-// В приведенном ниже примере `arg` будет `'my_token'`
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // useSWR + мутация-подобное API, но запрос не запускается автоматически.
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // Реализация fetcher-а.
+      // Дополнительный аргумент будет передан через свойство `arg` второго параметра.
+      // В приведенном ниже примере `arg` будет `'my_token'`
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // Запустите `updateUser` с определенным аргументом.
@@ -182,22 +178,18 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string } }) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* опции */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* опции */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // обработка ошибки
         }
diff --git a/pages/docs/mutation.zh-CN.mdx b/pages/docs/mutation.zh-CN.mdx
index 6b9e99e3..e683d296 100644
--- a/pages/docs/mutation.zh-CN.mdx
+++ b/pages/docs/mutation.zh-CN.mdx
@@ -128,21 +128,17 @@ SWR 还提供了 `useSWRMutation` 作为一个远程数据更改的 hook。远
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-// 实现 fetcher
-// 额外的参数可以通过第二个参数 `arg` 传入
-// 在下例中，`arg` 为 `'my_token'`
-async function updateUser(url, { arg }: { arg: string }) {
-  await fetch(url, {
-    method: 'POST',
-    headers: {
-      Authorization: `Bearer ${arg}`
-    }
-  })
-}
-
 function Profile() {
   // 一个类似 useSWR + mutate 的 API，但是它不会自动发送请求
-  const { trigger } = useSWRMutation('/api/user', updateUser, options)
+  const { trigger } = useSWRMutation(
+    '/api/user',
+    (url, { arg }: { arg: string }) =>
+      // 实现 fetcher
+      // 额外的参数可以通过第二个参数 `arg` 传入
+      // 在下例中，`arg` 为 `'my_token'`
+      fetch(url, { headers: { Authorization: `Bearer ${arg}` }}),
+    options
+  )
 
   return <button onClick={() => {
     // 以特定参数触发 `updateUser` 函数
@@ -179,22 +175,18 @@ function Profile() {
 ```tsx
 import useSWRMutation from 'swr/mutation'
 
-async function sendRequest(url, { arg }: { arg: { username: string }}) {
-  return fetch(url, {
-    method: 'POST',
-    body: JSON.stringify(arg)
-  }).then(res => res.json())
-}
-
 function App() {
-  const { trigger, isMutating } = useSWRMutation('/api/user', sendRequest, /* options */)
+  const { trigger, isMutating } = useSWRMutation(
+    '/api/user', 
+    () => fetch(url, { method: 'POST', body: JSON.stringify(arg) }).then(res => res.json())
+  )
 
   return (
     <button
       disabled={isMutating}
       onClick={async () => {
         try {
-          const result = await trigger({ username: 'johndoe' }, /* options */)
+          await trigger({ username: 'johndoe' }, /* options */)
         } catch (e) {
           // 错误处理
         }