gaspersic/freeCodeCamp
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

fix(guide): restructure curriculum guide articles (#36501)

Browse Source 
* fix: restructure certifications guide articles
* fix: added 3 dashes line before prob expl
* fix: added 3 dashes line before hints
* fix: added 3 dashes line before solutions
This commit is contained in:
Randell Dawson
2019-07-24 00:59:27 -07:00
committed by mrugesh
parent c911e77eed
commit 1494a50123
990 changed files with 13202 additions and 8628 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
guide/english/certifications/javascript-algorithms-and-data-structures/es6/prevent-object-mutation/index.md
View File

@@ -1,53 +1,48 @@
---
title: Prevent Object Mutation
---
![: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:
# Prevent Object Mutation
_You need to freeze the `MATH_CONSTANTS` object so that no one is able to alter the value of `PI`, add, or delete properties ._
## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 1
---
## Hints
### Hint 1
* _Use `Object.freeze()` to prevent mathematical constants from changing._
> _try to solve the problem now_
## Spoiler Alert!
![warning sign](//discourse-user-assets.s3.amazonaws.com/original/2X/2/2d6c412a50797771301e7ceabd554cef4edcd74d.gif)
---
## Solutions
**Solution Ahead!**
<details><summary>Solution 1 (Click to Show/Hide)</summary>
## ![:beginner:](https://forum.freecodecamp.com/images/emoji/emoji_one/beginner.png?v=3 ":beginner:") Basic code solution:
```javascript
function freezeObj() {
"use strict";
const MATH_CONSTANTS = {
PI: 3.14
};
function freezeObj() {
"use strict";
const MATH_CONSTANTS = {
PI: 3.14
};
Object.freeze(MATH_CONSTANTS);
try {
MATH_CONSTANTS.PI = 99;
} catch(ex) {
console.log(ex);
}
return MATH_CONSTANTS.PI;
}
const PI = freezeObj();
Object.freeze(MATH_CONSTANTS);
try {
MATH_CONSTANTS.PI = 99;
} catch (ex) {
console.log(ex);
}
return MATH_CONSTANTS.PI;
}
const PI = freezeObj();
```
# Code Explanation:
#### Code Explanation
By using Object.freeze() on `MATH_CONSTANTS` we can avoid manipulating it.
* By using Object.freeze() on `MATH_CONSTANTS` we can avoid manipulating it.
### Resources
#### Relevant Links
- ["Object.freeze()" - *MDN Javascript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze)
</details>
## ![:clipboard:](https://forum.freecodecamp.com/images/emoji/emoji_one/clipboard.png?v=3 ":clipboard:") NOTES FOR CONTRIBUTIONS:
* ![: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:")