diff --git a/index.js b/index.js
index 145e027..e03114c 100644
--- a/index.js
+++ b/index.js
@@ -1,12 +1,9 @@
 /**
- * {description of this file}
  * @author yutent<yutent.io@gmail.com>
  * @date 2020/09/16 14:52:58
  */
 
-import STATUS_TEXT from './lib/http-code-msg.json'
-
-const CHARSET_REGEXP = /;\s*charset\s*=/
+import STATUS_TEXT from './lib/http-code.js'
 
 export default class Response {
   constructor(req, res) {
@@ -45,16 +42,20 @@ export default class Response {
     if (this.rendered) {
       return
     }
-    let prev = this.get(key)
-    let value = val
+    var prev = this.get(key)
+    var value
+
+    if (Array.isArray(val)) {
+      value = val
+    } else {
+      value = [val]
+    }
 
     if (prev) {
       if (Array.isArray(prev)) {
         value = prev.concat(val)
-      } else if (Array.isArray(val)) {
-        value = [prev].concat(val)
       } else {
-        value = [prev, val]
+        value = [prev].concat(val)
       }
     }
     return this.set(key, value)
@@ -185,9 +186,13 @@ export default class Response {
       return this
     }
     if (arguments.length === 2) {
-      let value = Array.isArray(val) ? val.map(String) : String(val)
+      var value = Array.isArray(val) ? val.map(String) : String(val)
 
-      if (key.toLowerCase() === 'content-type' && !CHARSET_REGEXP.test(value)) {
+      if (
+        key.toLowerCase() === 'content-type' &&
+        typeof value === 'string' &&
+        value.indexOf('charset') < 0
+      ) {
         value += '; charset=utf-8'
       }
 
diff --git a/lib/http-code-msg.json b/lib/http-code-msg.json
deleted file mode 100644
index aece7af..0000000
--- a/lib/http-code-msg.json
+++ /dev/null
@@ -1,68 +0,0 @@
-{
-  "100": "Continue",
-  "101": "Switching Protocols",
-  "102": "Processing",
-  "200": "OK",
-  "201": "Created",
-  "202": "Accepted",
-  "203": "Non-Authoritative Information",
-  "204": "No Content",
-  "205": "Reset Content",
-  "206": "Partial Conten",
-  "207": "Multi-Status",
-  "208": "Already Reported",
-  "226": "IM Used",
-  "300": "Multiple Choices",
-  "301": "Moved Permanently",
-  "302": "Found",
-  "303": "See Other",
-  "304": "Not Modified",
-  "305": "Use Proxy",
-  "306": "Switch Proxy",
-  "307": "Temporary Redirect",
-  "308": "Permanent Redirect",
-  "400": "Bad Request",
-  "401": "Unauthorized",
-  "402": "Payment Required",
-  "403": "Forbidden",
-  "404": "Not Found",
-  "405": "Method Not Allowed",
-  "406": "Not Acceptable",
-  "407": "Proxy Authentication Required",
-  "408": "Request Timeout",
-  "409": "Conflict",
-  "410": "Gone",
-  "411": "Length Required",
-  "412": "Precondition Failed",
-  "413": "Request Entity Too Large",
-  "414": "Request-URI Too Long",
-  "415": "Unsupported Media Type",
-  "416": "Requested Range Not Satisfiable",
-  "417": "Expectation Failed",
-  "418": "I'm a teapot",
-  "420": "Enhance Your Caim",
-  "421": "Misdirected Request",
-  "422": "Unprocessable Entity",
-  "423": "Locked",
-  "424": "Failed Dependency",
-  "425": "Unordered Collection",
-  "426": "Upgrade Required",
-  "428": "Precondition Required",
-  "429": "Too Many Requests",
-  "431": "Request Header Fields Too Large",
-  "444": "No Response",
-  "450": "Blocked by Windows Parental Controls",
-  "451": "Unavailable For Legal Reasons",
-  "494": "Request Header Too Large",
-  "500": "Internal Server Error",
-  "501": "Not Implemented",
-  "502": "Bad Gateway",
-  "503": "Service Unavailable",
-  "504": "Gateway Timeout",
-  "505": "HTTP Version Not Supported",
-  "506": "Variant Also Negotiates",
-  "507": "Insufficient Storage",
-  "508": "Loop Detected",
-  "510": "Not Extended",
-  "511": "Network Authentication Required"
-}
\ No newline at end of file
diff --git a/lib/http-code.js b/lib/http-code.js
new file mode 100644
index 0000000..d293f16
--- /dev/null
+++ b/lib/http-code.js
@@ -0,0 +1,68 @@
+export default {
+  '100': 'Continue',
+  '101': 'Switching Protocols',
+  '102': 'Processing',
+  '200': 'OK',
+  '201': 'Created',
+  '202': 'Accepted',
+  '203': 'Non-Authoritative Information',
+  '204': 'No Content',
+  '205': 'Reset Content',
+  '206': 'Partial Conten',
+  '207': 'Multi-Status',
+  '208': 'Already Reported',
+  '226': 'IM Used',
+  '300': 'Multiple Choices',
+  '301': 'Moved Permanently',
+  '302': 'Found',
+  '303': 'See Other',
+  '304': 'Not Modified',
+  '305': 'Use Proxy',
+  '306': 'Switch Proxy',
+  '307': 'Temporary Redirect',
+  '308': 'Permanent Redirect',
+  '400': 'Bad Request',
+  '401': 'Unauthorized',
+  '402': 'Payment Required',
+  '403': 'Forbidden',
+  '404': 'Not Found',
+  '405': 'Method Not Allowed',
+  '406': 'Not Acceptable',
+  '407': 'Proxy Authentication Required',
+  '408': 'Request Timeout',
+  '409': 'Conflict',
+  '410': 'Gone',
+  '411': 'Length Required',
+  '412': 'Precondition Failed',
+  '413': 'Request Entity Too Large',
+  '414': 'Request-URI Too Long',
+  '415': 'Unsupported Media Type',
+  '416': 'Requested Range Not Satisfiable',
+  '417': 'Expectation Failed',
+  '418': "I'm a teapot",
+  '420': 'Enhance Your Caim',
+  '421': 'Misdirected Request',
+  '422': 'Unprocessable Entity',
+  '423': 'Locked',
+  '424': 'Failed Dependency',
+  '425': 'Unordered Collection',
+  '426': 'Upgrade Required',
+  '428': 'Precondition Required',
+  '429': 'Too Many Requests',
+  '431': 'Request Header Fields Too Large',
+  '444': 'No Response',
+  '450': 'Blocked by Windows Parental Controls',
+  '451': 'Unavailable For Legal Reasons',
+  '494': 'Request Header Too Large',
+  '500': 'Internal Server Error',
+  '501': 'Not Implemented',
+  '502': 'Bad Gateway',
+  '503': 'Service Unavailable',
+  '504': 'Gateway Timeout',
+  '505': 'HTTP Version Not Supported',
+  '506': 'Variant Also Negotiates',
+  '507': 'Insufficient Storage',
+  '508': 'Loop Detected',
+  '510': 'Not Extended',
+  '511': 'Network Authentication Required'
+}