add dropdown component

lib/utility/lgres.html

@@ -65,7 +65,7 @@
 
 lgres.init(document.body, {
     template: '/res.json',
-    callback: (res) => document.title = res.r('title', 'Default Title')
+    callback: res => document.title = res.r('title', 'Default Title')
 }).then(res => {
     document.querySelector('#header').innerText = res.r('header', 'My Header');
     const msg = lgres.lang.unknownError;

lib/utility/lgres.js

@@ -66,6 +66,7 @@ async function refreshLgres(template, lgres) {
     Object.defineProperty(lgres, 'r', {
         writable: false,
         configurable: false,
+        enumerable: false,
         value: function (key, defaultValue) {
             return getLanguage(this, key, defaultValue);
         }
@@ -76,16 +77,11 @@ async function refreshLgres(template, lgres) {
 
 function getLanguage(lgres, key, defaultValue) {
     let value = lgres[key];
-    if (value == null) {
-        value = defaultValue;
-    }
-    return value;
+    return value ?? defaultValue;
 }
 
 function applyLanguage(dom, result) {
-    if (dom == null) {
-        dom = document.body;
-    }
+    dom ??= document.body;
     for (let text of dom.querySelectorAll('[data-lgid]')) {
         const key = text.getAttribute('data-lgid');
         if (text.tagName === 'INPUT') {

lib/utility/request.html

@@ -103,7 +103,7 @@ request.post('api/query', { id: 101 })
     .then(result => console.log(result.data));
 
 request.upload('api/upload', data, {
-    progress: (ev) => {
+    progress: ev => {
         console.log(`loaded: ${ev.loaded}, total: ${ev.total}`);
     }
 })

lib/utility/strings.js

@@ -26,10 +26,7 @@ function padStart(s, num, char) {
     if (nullOrEmpty(s) || isNaN(num) || num <= s.length) {
         return s;
     }
-    if (char == null) {
-        char = ' ';
-    }
-    return char.repeat(num - s.length);
+    return (char ?? ' ').repeat(num - s.length);
 }
 
 export {