array helpers

Author: esadakman

6_kyu/arrayHelpers.md

@@ -0,0 +1,71 @@
+## [Array Helpers](https://www.codewars.com/kata/525d50d2037b7acd6e000534)
+
+- This kata is designed to test your ability to extend the functionality of built-in classes. In this case, we want you to extend the built-in Array class with the following methods: square(), cube(), average(), sum(), even() and odd().
+
+#### Explanation:
+
+- `square()` must return a copy of the array, containing all values squared
+- `cube()` must return a copy of the array, containing all values cubed
+- `average()` must return the average of all array values; on an empty array must return NaN (note: the empty array is not tested in Ruby!)
+- `sum()` must return the sum of all array values
+- `even()` must return an array of all even numbers
+- `odd()` must return an array of all odd numbers 2 _ 2 _ 1
+
+Note: the original array must not be changed in any case!
+
+#### Examples:
+
+```js
+var numbers = [1, 2, 3, 4, 5];
+
+numbers.square(); // must return [1, 4, 9, 16, 25]
+numbers.cube(); // must return [1, 8, 27, 64, 125]
+numbers.average(); // must return 3
+numbers.sum(); // must return 15
+numbers.even(); // must return [2, 4]
+numbers.odd(); // must return [1, 3, 5]
+```
+
+#### Solution:
+
+```js
+// Square every number in the array
+Array.prototype.square = function () {
+  return this.map((num) => num * num);
+};
+
+// Cube every number in the array
+Array.prototype.cube = function () {
+  return this.map((num) => Math.pow(num, 3));
+};
+
+// Calculate the average of the numbers in the array
+Array.prototype.average = function () {
+  if (this.length === 0) return NaN;
+  return this.sum() / this.length;
+};
+
+// Sum up all numbers in the array
+Array.prototype.sum = function () {
+  return this.reduce((acc, num) => acc + num, 0);
+};
+
+// Get all even numbers from the array
+Array.prototype.even = function () {
+  return this.filter((num) => num % 2 === 0);
+};
+
+// Get all odd numbers from the array
+Array.prototype.odd = function () {
+  return this.filter((num) => num % 2 !== 0);
+};
+
+let numbers = [1, 2, 3, 4, 5];
+
+console.log(numbers.square()); // [1, 4, 9, 16, 25]
+console.log(numbers.cube()); // [1, 8, 27, 64, 125]
+console.log(numbers.average()); // 3
+console.log(numbers.sum()); // 15
+console.log(numbers.even()); // [2, 4]
+console.log(numbers.odd()); // [1, 3, 5]
+```

README.md

@@ -672,5 +672,12 @@ Solutions to CodeWars programming tasks. I try to update every day
     <td><a href="5 kyu"> </a></td>
     <td><a href="others "></a></td>
   </tr> 
+  <tr>
+    <td><a href=" "> </a></td>
+    <td><a href="7 kyu"> </a></td>
+    <td><a href="https://github.com/esadakman/javaScript-coding-challenges/blob/master/6_kyu/arrayHelpers.md">arrayHelpers</a></td> 
+    <td><a href="5 kyu"> </a></td>
+    <td><a href="others "></a></td>
+  </tr> 
 </table>
 </p>