ui: fix problem_edit

packages/ui-default/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.6.19",
+  "version": "4.6.20",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",
@@ -28,7 +28,7 @@
     "babel-loader": "^8.2.2",
     "babel-plugin-lodash": "^3.3.4",
     "babel-plugin-prismjs": "^2.0.1",
-    "chalk": "^4.1.0",
+    "chalk": "^4.1.1",
     "classnames": "^2.3.1",
     "clipboard": "^2.0.8",
     "copy-webpack-plugin": "^6.1.1",
@@ -71,7 +71,7 @@
     "prop-types": "^15.7.2",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
-    "react-redux": "^7.2.3",
+    "react-redux": "^7.2.4",
     "react-split-pane": "^0.1.92",
     "redux": "^4.0.5",
     "redux-logger": "^3.0.6",

packages/ui-default/pages/problem_edit.page.js

@@ -236,19 +236,23 @@ export default new NamedPage(['problem_create', 'problem_edit'], (pagename) => {
     if (isObject) {
       if (content[i]) c = content[i];
       else {
-        const list = Object.keys(content).filter(l => l.startsWith(i));
+        const list = Object.keys(content).filter((l) => l.startsWith(i));
         if (list.length) c = content[list[0]];
-        i = list[0];
+        [i] = list;
       }
     } else c = content;
     if (typeof c !== 'string') c = JSON.stringify(c);
     $dom.val(c);
     function onChange(val) {
+      if (!isObject) {
+        content = { [i]: val };
+        isObject = true;
+      }
       const empty = /^\s*$/g.test(val);
       if (empty) delete content[i];
       else content[i] = val;
       $main.val(JSON.stringify(content));
     }
     CmEditor.getOrConstruct($dom, { upload, onChange });
-  })
+  });
 });