优化：支持控制是否显示

src/services/config.js

@@ -13,11 +13,13 @@ export function getVersion() {
 }
 
 export function getConfig(key) {
-  let item = _customConfig[key];
-  if (!item) {
-    item = _defConfig[key];
+  if (Object.prototype.hasOwnProperty.call(_customConfig, key)) {
+    return _customConfig[key];
   }
-  return item;
+  if (Object.prototype.hasOwnProperty.call(_defConfig, key)) {
+    return _defConfig[key];
+  }
+  return undefined;
 }
 
 export function setConfig(config) {