diff --git a/deno_dist/client/client.ts b/deno_dist/client/client.ts
index de04ee7f4..4d2d9cbf0 100644
--- a/deno_dist/client/client.ts
+++ b/deno_dist/client/client.ts
@@ -84,7 +84,6 @@ class ClientRequestImpl {
     }
 
     let methodUpperCase = this.method.toUpperCase()
-    let setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
 
     const headerValues: Record<string, string> = {
       ...(args?.header ?? {}),
@@ -117,7 +116,7 @@ class ClientRequestImpl {
       url = url + '?' + this.queryParams.toString()
     }
     methodUpperCase = this.method.toUpperCase()
-    setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
+    const setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
 
     // Pass URL string to 1st arg for testing with MSW and node-fetch
     return (opt?.fetch || fetch)(url, {
diff --git a/deno_dist/helper/ssg/ssg.ts b/deno_dist/helper/ssg/ssg.ts
index 1366526d7..9fb1b5ab9 100644
--- a/deno_dist/helper/ssg/ssg.ts
+++ b/deno_dist/helper/ssg/ssg.ts
@@ -271,7 +271,7 @@ export interface ToSSGAdaptorInterface<
  * The API might be changed.
  */
 export const toSSG: ToSSGInterface = async (app, fs, options) => {
-  let result: ToSSGResult | undefined = undefined
+  let result: ToSSGResult | undefined
   const getInfoPromises: Promise<unknown>[] = []
   const savePromises: Promise<string | undefined>[] = []
   try {
diff --git a/deno_dist/middleware/serve-static/index.ts b/deno_dist/middleware/serve-static/index.ts
index 5d43e4042..fb261865e 100644
--- a/deno_dist/middleware/serve-static/index.ts
+++ b/deno_dist/middleware/serve-static/index.ts
@@ -68,7 +68,7 @@ export const serveStatic = <E extends Env = Env>(
     }
 
     if (content) {
-      let mimeType: string | undefined = undefined
+      let mimeType: string | undefined
       if (options.mimes) {
         mimeType = getMimeType(path, options.mimes) ?? getMimeType(path)
       } else {
diff --git a/src/adapter/cloudflare-workers/utils.ts b/src/adapter/cloudflare-workers/utils.ts
index df18a82ed..d7c87d58c 100644
--- a/src/adapter/cloudflare-workers/utils.ts
+++ b/src/adapter/cloudflare-workers/utils.ts
@@ -12,7 +12,7 @@ export const getContentFromKVAsset = async (
   path: string,
   options?: KVAssetOptions
 ): Promise<ArrayBuffer | null> => {
-  let ASSET_MANIFEST: Record<string, string> = {}
+  let ASSET_MANIFEST: Record<string, string>
 
   if (options && options.manifest) {
     if (typeof options.manifest === 'string') {
diff --git a/src/client/client.ts b/src/client/client.ts
index 5c609ea61..68072ea99 100644
--- a/src/client/client.ts
+++ b/src/client/client.ts
@@ -84,7 +84,6 @@ class ClientRequestImpl {
     }
 
     let methodUpperCase = this.method.toUpperCase()
-    let setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
 
     const headerValues: Record<string, string> = {
       ...(args?.header ?? {}),
@@ -117,7 +116,7 @@ class ClientRequestImpl {
       url = url + '?' + this.queryParams.toString()
     }
     methodUpperCase = this.method.toUpperCase()
-    setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
+    const setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
 
     // Pass URL string to 1st arg for testing with MSW and node-fetch
     return (opt?.fetch || fetch)(url, {
diff --git a/src/helper/ssg/ssg.ts b/src/helper/ssg/ssg.ts
index 51be31fa2..1071244ad 100644
--- a/src/helper/ssg/ssg.ts
+++ b/src/helper/ssg/ssg.ts
@@ -271,7 +271,7 @@ export interface ToSSGAdaptorInterface<
  * The API might be changed.
  */
 export const toSSG: ToSSGInterface = async (app, fs, options) => {
-  let result: ToSSGResult | undefined = undefined
+  let result: ToSSGResult | undefined
   const getInfoPromises: Promise<unknown>[] = []
   const savePromises: Promise<string | undefined>[] = []
   try {
diff --git a/src/middleware/serve-static/index.ts b/src/middleware/serve-static/index.ts
index 930bb7d0c..3dafdc1be 100644
--- a/src/middleware/serve-static/index.ts
+++ b/src/middleware/serve-static/index.ts
@@ -68,7 +68,7 @@ export const serveStatic = <E extends Env = Env>(
     }
 
     if (content) {
-      let mimeType: string | undefined = undefined
+      let mimeType: string | undefined
       if (options.mimes) {
         mimeType = getMimeType(path, options.mimes) ?? getMimeType(path)
       } else {