feat(removeDuplicates): Add removeDuplicates function (#54)

closes #52

Author: ccabrales

src/index.js

@@ -12,6 +12,7 @@ import validateEmail from './validateEmail'
 import hex2rgb from './hex2rgb'
 import isNullOrWhitespace from './is-null-or-whitespace'
 import startsWith from './startsWith'
+import removeDuplicates from './remove-duplicates'
 
 export {
   flatten,
@@ -28,4 +29,5 @@ export {
   hex2rgb,
   isNullOrWhitespace,
   startsWith,
+  removeDuplicates,
 }

src/remove-duplicates.js

@@ -0,0 +1,17 @@
+export default removeDuplicates
+
+/**
+ * Original Source: http://stackoverflow.com/a/18328062
+ *
+ * This method will remove duplicate values in an array,
+ * leaving one of each value.
+ *
+ * @param {Array} arr - The Array to remove all duplicates from.
+ * @return {Array} - The Array without any duplicates.
+ */
+
+function removeDuplicates(arr) {
+  return arr.filter((item, index, inputArray) => {
+    return inputArray.indexOf(item) === index
+  })
+}

test/remove-duplicates.test.js

@@ -0,0 +1,23 @@
+import test from 'ava'
+import {removeDuplicates} from '../src'
+
+test('check array with duplicate strings', t => {
+    const array = ['hello', 'world', 'world', 'array'];
+    const expected = ['hello', 'world', 'array'];
+    const actual = removeDuplicates(array);
+    t.deepEqual(actual, expected);
+})
+
+test('check array with duplicate ints', t => {
+    const array = [1, 2, 3, 4, 4, 5, 5, 4, 1, 6];
+    const expected = [1, 2, 3, 4, 5, 6];
+    const actual = removeDuplicates(array);
+    t.deepEqual(actual, expected);
+})
+
+test('check array with no duplicates', t => {
+    const array = [1, 3, 5, 7, 9];
+    const expected = [1, 3, 5, 7, 9];
+    const actual = removeDuplicates(array);
+    t.deepEqual(actual, expected);
+})