diff --git a/client/client.js b/client/client.js
index da0b5d95..0e9938fb 100644
--- a/client/client.js
+++ b/client/client.js
@@ -278,7 +278,7 @@ function CloudCmdProto(DOM) {
         
         const isRefresh = true;
         const history = false;
-        const noCurrent = options ? options.noCurrent : false;
+        const noCurrent = options?.noCurrent;
         
         await CloudCmd.changeDir(path, {
             isRefresh,
diff --git a/client/dom/buffer.js b/client/dom/buffer.js
index 189f6423..8c4be473 100644
--- a/client/dom/buffer.js
+++ b/client/dom/buffer.js
@@ -26,9 +26,8 @@ function BufferProto() {
 
     function getNames() {
         const files = DOM.getActiveFiles();
-        const names = DOM.getFilenames(files);
         
-        return names;
+        return DOM.getFilenames(files);
     }
 
     function addCutClass() {
diff --git a/client/dom/current-file.js b/client/dom/current-file.js
index 2ab0ab51..1785a4c8 100644
--- a/client/dom/current-file.js
+++ b/client/dom/current-file.js
@@ -109,9 +109,8 @@ module.exports.getCurrentDirName = () => {
         .replace(/\/$/, '');
     
     const substr = href.substr(href, href.lastIndexOf('/'));
-    const ret = href.replace(`${substr}/`, '') || '/';
     
-    return ret;
+    return href.replace(`${substr}/`, '') || '/';
 };
 
 /**
@@ -266,7 +265,7 @@ module.exports.getCurrentByPosition = ({x, y}) => {
 module.exports.isCurrentFile = (currentFile) => {
     if (!currentFile)
         return false;
-
+    
     return DOM.isContainClass(currentFile, CURRENT_FILE);
 };
 
diff --git a/client/dom/index.js b/client/dom/index.js
index adf2abc9..acefb5b9 100644
--- a/client/dom/index.js
+++ b/client/dom/index.js
@@ -1,5 +1,6 @@
 'use strict';
 
+const isString = (a) => typeof a === 'string';
 /* global CloudCmd */
 const Util = require('../../common/util');
 
@@ -116,9 +117,8 @@ module.exports.getCurrentDirName = () => {
         .replace(/\/$/, '');
     
     const substr = href.substr(href, href.lastIndexOf('/'));
-    const ret = href.replace(`${substr}/`, '') || '/';
     
-    return ret;
+    return href.replace(`${substr}/`, '') || '/';
 };
 
 /**
@@ -143,9 +143,7 @@ module.exports.getNotCurrentDirPath = () => {
         active: false,
     });
     
-    const path = DOM.getCurrentDirPath(panel);
-    
-    return path;
+    return DOM.getCurrentDirPath(panel);
 };
 
 /**
@@ -189,9 +187,8 @@ module.exports.getActiveFiles = () => {
 
 module.exports.getCurrentDate = (currentFile) => {
     const current = currentFile || DOM.getCurrentFile();
-    const date = DOM.getByDataName('js-date', current).textContent;
     
-    return date;
+    return DOM.getByDataName('js-date', current).textContent;
 };
 
 /**
@@ -438,7 +435,7 @@ module.exports.setHistory = (data, title, url) => {
 module.exports.isSelected = (selected) => {
     if (!selected)
         return false;
-
+    
     return DOM.isContainClass(selected, SELECTED_FILE);
 };
 
@@ -479,7 +476,7 @@ module.exports.getFilenames = (files) => {
 module.exports.checkStorageHash = async (name) => {
     const nameHash = `${name}-hash`;
     
-    if (typeof name !== 'string')
+    if (!isString(name))
         throw Error('name should be a string!');
     
     const [loadHash, storeHash] = await Promise.all([
@@ -723,7 +720,7 @@ module.exports.changePanel = () => {
 module.exports.getPackerExt = (type) => {
     if (type === 'zip')
         return '.zip';
-
+    
     return '.tar.gz';
 };
 
@@ -749,7 +746,7 @@ module.exports.duplicatePanel = async () => {
     const getPath = (isDir) => {
         if (isDir)
             return Info.path;
-
+        
         return Info.dirPath;
     };
     
diff --git a/client/key/index.js b/client/key/index.js
index 094d4e75..6fe55307 100644
--- a/client/key/index.js
+++ b/client/key/index.js
@@ -111,9 +111,8 @@ function getSymbol(shift, keyCode) {
 function fromCharCode(keyIdentifier) {
     const code = keyIdentifier.substring(2);
     const hex = parseInt(code, 16);
-    const char = String.fromCharCode(hex);
     
-    return char;
+    return String.fromCharCode(hex);
 }
 
 async function switchKey(event) {
diff --git a/client/listeners/index.js b/client/listeners/index.js
index 02038407..dab178e3 100644
--- a/client/listeners/index.js
+++ b/client/listeners/index.js
@@ -94,7 +94,7 @@ function header() {
 function getPath(el, path = []) {
     if (!el)
         return path;
-
+    
     return getPath(el.parentElement, path.concat(el));
 }
 
@@ -115,9 +115,8 @@ module.exports.initKeysPanel = () => {
         const {id} = target;
         const operation = (name) => {
             const {Operation} = CloudCmd;
-            const fn = Operation.show.bind(null, name);
             
-            return fn;
+            return Operation.show.bind(null, name);
         };
         
         const clickFuncs = {
@@ -143,7 +142,7 @@ module.exports.initKeysPanel = () => {
 const getPanel = (side) => {
     if (!itype.string(side))
         return side;
-
+    
     return DOM.getByDataName(`js-${side}`);
 };
 
diff --git a/client/modules/config/index.js b/client/modules/config/index.js
index 5c586c48..76fed60b 100644
--- a/client/modules/config/index.js
+++ b/client/modules/config/index.js
@@ -75,9 +75,7 @@ function getHost() {
         protocol,
     } = location;
     
-    const href = origin || `${protocol}//${host}`;
-    
-    return href;
+    return origin || `${protocol}//${host}`;
 }
 
 function initSocket() {
diff --git a/client/modules/edit.js b/client/modules/edit.js
index ce8848af..44392dcb 100644
--- a/client/modules/edit.js
+++ b/client/modules/edit.js
@@ -2,6 +2,7 @@
 
 'use strict';
 
+const isFn = (a) => typeof a === 'function';
 const montag = require('montag');
 
 const {promisify} = require('es6-promisify');
@@ -54,7 +55,7 @@ function create() {
 }
 
 function checkFn(name, fn) {
-    if (typeof fn !== 'function')
+    if (!isFn(fn))
         throw Error(`${name} should be a function!`);
 }
 
diff --git a/client/modules/menu.js b/client/modules/menu.js
index c0dc664f..4a82d8bb 100644
--- a/client/modules/menu.js
+++ b/client/modules/menu.js
@@ -77,7 +77,7 @@ function getPosition(position) {
             x: position.x,
             y: position.y,
         };
-
+    
     return getCurrentPosition();
 }
 
@@ -196,9 +196,8 @@ function isPath(x, y) {
     
     const el = document.elementFromPoint(x, y);
     const elements = panel.querySelectorAll('[data-name="js-path"] *');
-    const is = ~[].indexOf.call(elements, el);
     
-    return is;
+    return ~[].indexOf.call(elements, el);
 }
 
 function beforeShow(callback, params) {
diff --git a/client/modules/view/index.js b/client/modules/view/index.js
index 377c5e7f..893e9df1 100644
--- a/client/modules/view/index.js
+++ b/client/modules/view/index.js
@@ -2,6 +2,7 @@
 
 'use strict';
 
+const isString = (a) => typeof a === 'string';
 require('../../../css/view.css');
 
 const rendy = require('rendy');
@@ -317,7 +318,7 @@ async function getMediaElement(src) {
 }
 
 function check(src) {
-    if (typeof src !== 'string')
+    if (!isString(src))
         throw Error('src should be a string!');
 }