Merge 7d572bd118 into 09f408a1b7

01_Day_JavaScript_Refresher/01_javascript_refresher.md

@@ -1724,7 +1724,7 @@ for (let i = 0; i < 3; i++) {
 // console.log(i), Uncaught ReferenceError: gravity is not defined
 ```
 
-The scope _let_ and _const_ is the same. The difference is only reassigning. We can not change or reassign the value of const variable. I would strongly suggest you to use _let_ and _const_, by using _let_ and _const_ you will writ clean code and avoid hard to debug mistakes. As a rule of thumb, you can use _let_ for any value which change, _const_ for any constant value, and for array, object, arrow function and function expression.
+The scope _let_ and _const_ is the same. The difference is only reassigning. We can not change or reassign the value of const variable. I would strongly suggest you to use _let_ and _const_, by using _let_ and _const_ you will write clean code and avoid hard to debug mistakes. As a rule of thumb, you can use _let_ for any value which change, _const_ for any constant value, and for array, object, arrow function and function expression.
 
 ### 7. Object
 
@@ -2133,10 +2133,12 @@ const products = [
 ```
 
 Imagine you are getting the above users collection from a MongoDB database.
-a. Create a function called signUp which allows user to add to the collection. If user exists, inform the user that he has already an account.  
+
+ a. Create a function called signUp which allows user to add to the collection. If user exists, inform the user that he has already an account.  
  b. Create a function called signIn which allows user to sign in to the application
 
 3. The products array has three elements and each of them has six properties.
+
    a. Create a function called rateProduct which rates the product
    b. Create a function called averageRating which calculate the average rating of a product
 

21_Introducing_Hooks/21_introducing_hooks.md

@@ -14,7 +14,7 @@
 
 </div>
 
-[<< Day 20](../20_projects/20_projects.md) | [Day 22>>]()
+[<< Day 20](../20_projects/20_projects.md) | [Day 22>>](../22_Form_Using_Hooks/22_form_using_hooks.md)
 
 ![30 Days of React banner](../images/30_days_of_react_banner_day_21.jpg)
 
@@ -404,4 +404,4 @@ ReactDOM.render(<App />, rootElement)
 Convert everything you wrote to React hooks.
 
 🎉 CONGRATULATIONS ! 🎉
-[<< Day 20](../20_projects/20_projects.md) | [Day 22>>]()
+[<< Day 20](../20_projects/20_projects.md) | [Day 22>>](../22_Form_Using_Hooks/22_form_using_hooks.md)