Add "Merge two arrays" kata

Author: juanantonioledesma

7-kyu/merge-two-arrays.md

@@ -0,0 +1,40 @@
+<h1>Merge two arrays <sup><sup>7 Kyu</sup></sup></h1>
+
+<sup>
+  <a href="https://www.codewars.com/kata/583af10620dda4da270000c5">
+    <strong>LINK TO THE KATA</strong>
+  </a> - <code>FUNDAMENTALS</code> <code>ARRAYS</code>
+</sup>
+
+## Description
+
+Write a function that combines two arrays by alternatingly taking elements from each array in turn.
+
+Examples:
+
+```
+[a, b, c, d, e], [1, 2, 3, 4, 5] becomes  [a, 1, b, 2, c, 3, d, 4, e, 5]
+
+[1, 2, 3], [a, b, c, d, e, f] becomes [1, a, 2, b, 3, c, d, e, f]
+```
+
+Points:
+
+1. The arrays may be of different lengths, with at least one character/digit.
+2. One array will be of string characters (in lower case, a-z), a second of integers (all positive starting at 1).
+
+## Solution
+
+```javascript
+const mergeArrays = (a, b) => {
+  const result = []
+  const biggerArrayLength = a.length >= b.length ? a.length : b.length
+
+  for (let i = 0; i < biggerArrayLength; i++) {
+    if (a[i] !== undefined) result.push(a[i])
+    if (b[i] !== undefined) result.push(b[i])
+  }
+
+  return result
+}
+```

README.md

@@ -80,6 +80,7 @@ JavaScript katas on Codewars are programming challenges that help you improve yo
 - **[Homogenous arrays](./7-kyu/homogenous-arrays.md)**
 - **[L2: Triple X](./7-kyu/l2-triple-x.md)**
 - **[Letterbox Paint-Squad](./7-kyu/letterbox-paint-squad.md)**
+- **[Merge two arrays](./7-kyu/merge-two-arrays.md)**
 - **[Return the closest number multiple of 10](./7-kyu/return-the-closest-number-multiple-of-10.md)**
 - **[Sort Numbers](./7-kyu/sort-numbers.md)**
 - **[Sum of two lowest positive integers](./7-kyu/sum-of-two-lowest-positive-integers.md)**