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fix(guide): ES6 markup and edit fixes and improvements (#34691) 

- Remove image of phantom
- Remove notes for contributors
- Links to bottom and to markdown + some more
- Alternative code solution

### Notes:
- The guide article mentions the challenge can be solved by using `reduce()` but I couldn't find a way to do so. It might be better to remove that reference and the bottom link until someone provides one.
- The alternative code solution I provided uses a simpler way (in my opinion) to check if the values are integers but does not differ much from the original one. If necessary, feel free to remove it and go on with just the fixes.
pull/23772/head^2
Adrian Skar 2018-12-27 13:39:51 +01:00 committed by Aditya
parent bd244f9958
commit 6300a5339f
1 changed files with 22 additions and 18 deletions
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40
guide/english/certifications/javascript-algorithms-and-data-structures/es6/write-higher-order-arrow-functions/index.md
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@ -1,11 +1,9 @@
---
title: Write Higher Order Arrow Functions
---
![](//discourse-user-assets.s3.amazonaws.com/original/2X/3/3c8584a085a0deaea66b3400e6321eeadab552a2.jpg)
![:triangular_flag_on_post:](https://forum.freecodecamp.com/images/emoji/emoji_one/triangular_flag_on_post.png?v=3 ":triangular_flag_on_post:") Remember to use <a>**`Read-Search-Ask`**</a> if you get stuck. Try to pair program ![:busts_in_silhouette:](https://forum.freecodecamp.com/images/emoji/emoji_one/busts_in_silhouette.png?v=3 ":busts_in_silhouette:") and write your own code ![:pencil:](https://forum.freecodecamp.com/images/emoji/emoji_one/pencil.png?v=3 ":pencil:")
### Problem Explanation:
### Problem explanation:
We need to compute and square values from the `realNumberArray` and store them in the variable `squaredIntegers` using the `map()`, `filter()`, and/or `reduce()` functions.
@ -27,13 +25,13 @@ We need to compute and square values from the `realNumberArray` and store them i
> _try to solve the problem now_
## Spoiler Alert!
## Spoiler alert!
![warning sign](//discourse-user-assets.s3.amazonaws.com/original/2X/2/2d6c412a50797771301e7ceabd554cef4edcd74d.gif)
**Solution ahead!**
## ![:beginner:](https://forum.freecodecamp.com/images/emoji/emoji_one/beginner.png?v=3 ":beginner:") Basic Code Solution:
## ![:beginner:](https://forum.freecodecamp.com/images/emoji/emoji_one/beginner.png?v=3 ":beginner:") Code solution:
```javascript
const squareList = (arr) => {
"use strict";
@ -45,23 +43,29 @@ We need to compute and square values from the `realNumberArray` and store them i
const squaredIntegers = squareList(realNumberArray);
console.log(squaredIntegers);
```
![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") <a href='https://codepen.io/dylantyates/pen/WyWoYJ' target='_blank' rel='nofollow'>Run Code</a>
# Code Explanation:
- [Run code at codepen.io](https://codepen.io/dylantyates/pen/WyWoYJ)
### Code explanation:
Uses the operator `filter()` and `map()` functions to square all positive integers in a given array.
#### Relevant Links
* <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map' target='_blank' rel='nofollow'>map()</a>
* <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter' target='_blank' rel='nofollow'>filter()</a>
* <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce' target='_blank' rel='nofollow'>reduce()</a>
## Alternative code solution:
```javascript
## ![:clipboard:](https://forum.freecodecamp.com/images/emoji/emoji_one/clipboard.png?v=3 ":clipboard:") NOTES FOR CONTRIBUTIONS:
// change code below this line
const squaredIntegers = arr.filter((param) => Number.isInteger(param) && param >= 0).map(x => x * x);
// change code above this line
* ![:warning:](https://forum.freecodecamp.com/images/emoji/emoji_one/warning.png?v=3 ":warning:") **DO NOT** add solutions that are similar to any existing solutions. If you think it is **_similar but better_**, then try to merge (or replace) the existing similar solution.
* Add an explanation of your solution.
* Categorize the solution in one of the following categories — **Basic**, **Intermediate** and **Advanced**. ![:traffic_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/traffic_light.png?v=3 ":traffic_light:")
* Please add your username only if you have added any **relevant main contents**. (![:warning:](https://forum.freecodecamp.com/images/emoji/emoji_one/warning.png?v=3 ":warning:") **_DO NOT_** _remove any existing usernames_)
```
- [Run code at repl.it](https://repl.it/@AdrianSkar/ES6-Write-higher-order-arrow-functions)
### Code explanation
This does basically the same but uses the `isInteger()` method to check the numbers.
> See ![:point_right:](https://forum.freecodecamp.com/images/emoji/emoji_one/point_right.png?v=3 ":point_right:") <a href='http://forum.freecodecamp.com/t/algorithm-article-template/14272' target='_blank' rel='nofollow'>**`Wiki Challenge Solution Template`**</a> for reference.
### Resources
- ["Array.prototype.map()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map)
- ["Array.prototype.filter()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter)
- ["Array.prototype.reduce()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce)
- ["Number.isInteger()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger)
- ["Math.pow()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/pow)