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

solution Work with Dynamic Data in D3 (#27204)

Browse Source 
changed stub to full explanation page with relevant links and basic/intermediate solutions
This commit is contained in:
Bannon Tanner
2019-03-07 07:24:44 -06:00
committed by The Coding Aviator
parent a8334f88c0
commit cfb6454775
1 changed files with 106 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

109
guide/english/certifications/data-visualization/data-visualization-with-d3/work-with-dynamic-data-in-d3/index.md
View File

@@ -3,8 +3,111 @@ title: Work with Dynamic Data in D3
---
## Work with Dynamic Data in D3
This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/data-visualization/data-visualization-with-d3/work-with-dynamic-data-in-d3/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
![: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:")
<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
### Problem Explanation:
<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds -->
This challenge introduces using JavaScript callback functions as arguments to D3 methods. Since D3 is a JavaScript object, it has no problem following the same syntax rules
#### Relevant Links
* [JavaScript Callback Function](https://developer.mozilla.org/en-US/docs/Glossary/Callback_function)
* [JavaScript Arrow Function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions)
## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 1
* As in the example, your callback function should target each datum, `d` is used for brevity and as convention for each datum
> _try to solve the problem now_
## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 2
* All of the methods are chained together. Since `data()` and `enter()` precede the `text()` method, the following method calls will be for each datum and executed separately
> _try to solve the problem now_
## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 3
* As in the example, use an arrow function to target each `d` as a parameter and insert that parameter as a variable into the `text()` method
> _try to solve the problem now_
## Spoiler Alert!
**Solution ahead!**
## ![:beginner:](https://forum.freecodecamp.com/images/emoji/emoji_one/beginner.png?v=3 ":beginner:") Basic Code Solution:
```javascript
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
d3.select("body").selectAll("h2")
.data(dataset)
.enter()
.append("h2")
.text((d) => d + ' USD');
</script>
</body>
```
# Code Explanation:
* `d3` is used to target the D3 object
* `select('body')` targets the 'body' element of the HTML document
* `selectAll('h2')` targets the existing 'h2' nodes that are children to the 'body' element
* `data(dataset)` tells D3 that the data to be used is held within the variable `dataset`
* `enter()` returns placeholder nodes for each datum that has no corresponding DOM element in the selection
* `append('h2')` turns these placesholders in to 'h2' elements
* `text((d) => d + ' USD')` uses JavaScripts callback functionality to insert each datum, `d`, as the text for each 'h2' node created previously and concatenates the required ' USD'
#### Relevant Links
* [JavaScript Callback Function](https://developer.mozilla.org/en-US/docs/Glossary/Callback_function)
* [JavaScript Arrow Function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions)
## ![:sunflower:](https://forum.freecodecamp.com/images/emoji/emoji_one/sunflower.png?v=3 ":sunflower:") Intermediate Code Solution:
```javascript
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
d3.select("body").selectAll("h2")
.data(dataset)
.enter()
.append("h2")
.text((d) => `${d} USD`);
</script>
</body>
```
# Code Explanation:
* `d3` is used to target the D3 object
* `select('body')` targets the 'body' element of the HTML document
* `selectAll('h2')` targets the existing 'h2' nodes that are children to the 'body' element
* `data(dataset)` tells D3 that the data to be used is held within the variable `dataset`
* `enter()` returns placeholder nodes for each datum that has no corresponding DOM element in the selection
* `append('h2')` turns these placesholders in to 'h2' elements
* `text((d) => ```${d} USD```)` uses JavaScripts callback functionality to insert each datum, `d`, as the text for each 'h2' node created previously. It also makes use of JavaScript template literals to avoid string concatenation
#### Relevant Links
* [JavaScript Callback Function](https://developer.mozilla.org/en-US/docs/Glossary/Callback_function)
* [JavaScript Arrow Function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions)
* [JavaScript Template Literals](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals)
## ![: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:")
* 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_)
> 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.