Merge pull request #78 from edx/schen/EDUCATOR-3925

fix(bug): make sure gradebook rounding handle null input

package-lock.json

@@ -10469,14 +10469,12 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -10496,8 +10494,7 @@
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "console-control-strings": {
           "version": "1.1.0",
@@ -10645,7 +10642,6 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }

src/components/Gradebook/index.jsx

@@ -176,7 +176,7 @@ export default class Gradebook extends React.Component {
     return 'Tracks';
   };
 
-  roundGrade = percent => parseFloat(percent.toFixed(DECIMAL_PRECISION));
+  roundGrade = percent => parseFloat((percent || 0).toFixed(DECIMAL_PRECISION));
 
   formatter = {
     percent: (entries, areGradesFrozen) => entries.map((entry) => {