In this article we are going to solve **2** **Codewars' [6**th kyu ] problems using **Javascript (ES6) **and ** **discuss approaches how problems can be solved **.**

Codewars is a great site for improving your problem solving skills and it's also great for discovering different approaches of other developers in solving each problems.

Problems at code wars are label by difficulty as **kyu, **[1st kyu] being the hardest and [8th kyu] being the easiest.

Let's now start with our first problem.

#### 1. Matrix Addition

Codewars link: **https://www.codewars.com/kata/matrix-addition/train/javascript**

**The problem is :**

**The solution:**

Non ES6 approach:

We have created **m** as the variable that will hold the sum of cells in both **a **and **b **in same **row** and **col.**

And every row iteration we are adding an empty **1d **array to **m, **so that we can store the sum of same cells for both **a **and **b.**

And would you believe the approach above can be reduced into a **single line of code**?

ES6 Approach:

In this approach we have used **arrow **function of Javascript, to omit the **function()** keyword, to make it more shorter.

Also using **arrow** function would omit the **return **keyword.

We have used **map** here to mutate the matrix's value, and we have another inner **map** since we are dealing with 2d array here.

Same as our solution above we have **r ** and **c **which denotes the row and column of the cells we are adding .

2. Find the unique number

Codewars link: **https://www.codewars.com/kata/find-the-unique-number-1/train/javascript**

**The problem is :**

The solution:

Non ES6 approach:

**uniqObj** is a variable that will hold the unique elements in the array as key.

**hasOwnProperty()** is an **Object** method that returns a boolean value if the key already exist in the object or not, if it exists we are setting it to **true** meaning the it is not unique, otherwise initialize it to **false**.

**Object.keys()** gets all the keys inside the object needed to iterate into the object values to find **false** in it, meaning it is a unique number then return the **parseInt** value of that key.

ES6 Approach:

Uses the same idea as we did above, but instead of declaring a var **uniqObj** and using **forEach** to accumulate its value, we used **reduce() **instead, as well as to finding which key is the only unique number.

Instead of using **if **in checking to the unique number, we used a ternary operator.

We also change **parseInt(strNumber) **into **+strNumber,** which is the shorthand for parsing int.

That ends our article in Solving 6th kyu Codewars problem using ES6.

Check out the 7th kyu version of this article: **http://onecompileman.com/blogs/3**