fixed

1-js/04-object-basics/01-object/3-is-empty/solution.md

@@ -2,7 +2,7 @@ Just loop over the object and `return false` immediately if there's at least one
 
 ```js
 function isEmpty(obj) {
-  for(let key in obj) {
+  for (let key in obj) {
     return false;
   }
   return true;

1-js/04-object-basics/01-object/5-sum-object/solution.md

@@ -4,10 +4,10 @@ let salaries = {
   John: 100,
   Ann: 160,
   Pete: 130
-}
+};
 
 let sum = 0;
-for(let key in salaries) {
+for (let key in salaries) {
   sum += salaries[key];
 }
 

1-js/04-object-basics/05-object-toprimitive/article.md

@@ -213,7 +213,7 @@ For instance:
 ```smart header="Historical notes"
 For historical reasons, methods `toString` or `valueOf` *should* return a primitive: if any of them returns an object, then there's no error, but that object is ignored (like if the method didn't exist).
 
-In contrast, `Symbol.toPrimitive` *must* return an primitive, otherwise there will be an error.
+In contrast, `Symbol.toPrimitive` *must* return a primitive, otherwise, there will be an error.
 ```
 
 ## Summary