feat(Data-Structures/Array): add function to find last element in an …

…array

Data-Structures/Array/FindLastElement.js

@@ -0,0 +1,17 @@
+/**
+ * (https://www.geeksforgeeks.org/get-the-first-and-last-item-in-an-array-using-javascript/)
+ * This function will accept an array and
+ * return the last element of the array.
+ * If the array is empty, it will return undefined.
+ * @param {Array} arr array with elements of any data type
+ * @returns {*} last element of the array
+ */
+const FindLastElement = (arr) => {
+    if (arr.length === 0) {
+      return undefined;
+    }
+    return arr[arr.length - 1];
+  };
+
+  export { FindLastElement };
+

Data-Structures/Array/test/FindLastElement.test.js

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+import { FindLastElement } from '../FindLastElement';
+import each from 'jest-each';
+
+describe('find last element of an array', () => {
+  each`
+  array          | expected
+  ${[]}          | ${undefined}
+  ${[1]}         | ${1}
+  ${[1, 2, 3, 4]} | ${4}
+  `.test('returns $expected when given $array', ({ array, expected }) => {
+    expect(FindLastElement(array)).toEqual(expected);
+  });
+});