Minor refactoring

src/controllers/sheetmanage.js

@@ -78,7 +78,7 @@ const sheetmanage = {
         let copyWord = "(" + locale_info.copy;
         const copy_i = name.toString().indexOf(copyWord);
 
-        if (copy_i > -1) {
+        if (~copy_i) {
             name = name.toString().substring(0, copy_i);
         }
 
@@ -86,17 +86,17 @@ const sheetmanage = {
         let nameCopy = name + copyWord;
         const sheetNames = [];
 
-        for(let i = 0; i < file.length; i++){
+        for (let i = 0; i < file.length; i++) {
             let fileName = file[i].name.toString();
             sheetNames.push(fileName);
             let st_i = fileName.indexOf(nameCopy);
 
-            if(st_i === 0){
+            if(st_i === 0) {
                 index = index || 2;
                 let ed_i = fileName.indexOf(")", st_i + nameCopy.length);
                 let num = fileName.substring(st_i + nameCopy.length, ed_i);
 
-                if(isRealNum(num)){
+                if (isRealNum(num)) {
                     if(parseInt(num) >= index){
                         index = parseInt(num) + 1;
                     }