chore: use rest params (#1393)

Author: tinovyatkin

lib/request.js

@@ -622,15 +622,14 @@ module.exports = {
    *
    *     this.is('html'); // => false
    *
-   * @param {String|Array} types...
+   * @param {String|String[]} [type]
+   * @param {String[]} [types]
    * @return {String|false|null}
    * @api public
    */
 
-  is(types) {
-    if (!types) return typeis(this.req);
-    if (!Array.isArray(types)) types = [].slice.call(arguments);
-    return typeis(this.req, types);
+  is(type, ...types) {
+    return typeis(this.req, type, ...types);
   },
 
   /**

lib/response.js

@@ -389,16 +389,14 @@ module.exports = {
    * Check whether the response is one of the listed types.
    * Pretty much the same as `this.request.is()`.
    *
-   * @param {String|Array} types...
+   * @param {String|String[]} [type]
+   * @param {String[]} [types]
    * @return {String|false}
    * @api public
    */
 
-  is(types) {
-    const type = this.type;
-    if (!types) return type || false;
-    if (!Array.isArray(types)) types = [].slice.call(arguments);
-    return typeis(type, types);
+  is(type, ...types) {
+    return typeis(this.type, type, ...types);
   },
 
   /**