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

fix(curriculum): Convert blockquote elements to triple backtick syntax for Data Visualization (#35995)

Browse Source 
* fix: convert data visualization

* fix: reverted to blockquote

* fix: changed js to json

Co-Authored-By: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>

* fix: cleaned up code

Co-Authored-By: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>
This commit is contained in:
Randell Dawson
2019-05-14 05:04:05 -07:00
committed by Tom
parent 933350c148
commit dd6011b2cc
18 changed files with 211 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/access-the-json-data-from-an-api.english.md
View File

@ -15,7 +15,12 @@ The first and last character you see in the JSON data are square brackets <code>
You learned earlier that objects contain "key-value pairs" that are separated by commas. In the Cat Photo example, the first object has <code>"id":0</code> where "id" is a key and 0 is its corresponding value. Similarly, there are keys for "imageLink", "altText", and "codeNames". Each cat photo object has these same keys, but with different values.
Another interesting "key-value pair" in the first object is <code>"codeNames":["Juggernaut","Mrs. Wallace","ButterCup"]</code>. Here "codeNames" is the key and its value is an array of three strings. It's possible to have arrays of objects as well as a key with an array as a value.
Remember how to access data in arrays and objects. Arrays use bracket notation to access a specific index of an item. Objects use either bracket or dot notation to access the value of a given property. Here's an example that prints the "altText" of the first cat photo - note that the parsed JSON data in the editor is saved in a variable called <code>json</code>:
<blockquote>console.log(json[0].altText);<br>// Prints "A white cat wearing a green helmet shaped melon on its head."</blockquote>
```js
console.log(json[0].altText);
// Prints "A white cat wearing a green helmet shaped melon on its head."
```
</section>
## Instructions

27
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/convert-json-data-to-html.english.md
View File

@ -11,14 +11,37 @@ You can use a <code>forEach</code> method to loop through the data since the cat
First, declare an html variable with <code>var html = "";</code>.
Then, loop through the JSON, adding HTML to the variable that wraps the key names in <code>strong</code> tags, followed by the value. When the loop is finished, you render it.
Here's the code that does this:
<blockquote>json.forEach(function(val) {</br>&nbsp;&nbsp;var keys = Object.keys(val);</br>&nbsp;&nbsp;html += "&lt;div class = 'cat'&gt;";</br>&nbsp;&nbsp;keys.forEach(function(key) {</br>&nbsp;&nbsp;&nbsp;&nbsp;html += "&lt;strong&gt;" + key + "&lt;/strong&gt;: " + val[key] + "&lt;br&gt;";</br>&nbsp;&nbsp;});</br>&nbsp;&nbsp;html += "&lt;/div&gt;&lt;br&gt;";</br>});</blockquote>
```js
json.forEach(function(val) {
var keys = Object.keys(val);
html += "<div class = 'cat'>";
keys.forEach(function(key) {
html += "<strong>" + key + "</strong>: " + val[key] + "<br>";
});
html += "</div><br>";
});
```
</section>
## Instructions
<section id='instructions'>
Add a <code>forEach</code> method to loop over the JSON data and create the HTML elements to display it.
Here is some example JSON
<blockquote>[</br>&nbsp;&nbsp;{</br>&nbsp;&nbsp;&nbsp;&nbsp;"id":0,</br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"imageLink":"https://s3.amazonaws.com/freecodecamp/funny-cat.jpg",</br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"altText":"A white cat wearing a green helmet shaped melon on its head. ",</br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"codeNames":[ "Juggernaut", "Mrs. Wallace", "Buttercup"</br>&nbsp;&nbsp;&nbsp;&nbsp;]</br>&nbsp;&nbsp;}</br>]</blockquote>
```json
[
{
"id":0,
"imageLink":"https://s3.amazonaws.com/freecodecamp/funny-cat.jpg",
"altText":"A white cat wearing a green helmet shaped melon on its head. ",
"codeNames":[ "Juggernaut", "Mrs. Wallace", "Buttercup"
]
}
]
```
</section>
## Tests

10
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/get-geolocation-data-to-find-a-users-gps-coordinates.english.md
View File

@ -11,7 +11,15 @@ The navigator will get the user's current longitude and latitude.
You will see a prompt to allow or block this site from knowing your current location. The challenge can be completed either way, as long as the code is correct.
By selecting allow, you will see the text on the output phone change to your latitude and longitude.
Here's code that does this:
<blockquote>if (navigator.geolocation){<br>&nbsp;&nbsp;navigator.geolocation.getCurrentPosition(function(position) {<br>&nbsp;&nbsp;&nbsp;&nbsp;document.getElementById('data').innerHTML="latitude: "+ position.coords.latitude + "&lt;br&gt;longitude: " + position.coords.longitude;<br>&nbsp;&nbsp;});<br>}</blockquote>
```js
if (navigator.geolocation){
navigator.geolocation.getCurrentPosition(function(position) {
document.getElementById('data').innerHTML="latitude: " + position.coords.latitude + "<br>longitude: " + position.coords.longitude;
});
}
```
First, it checks if the <code>navigator.geolocation</code> object exists. If it does, the <code>getCurrentPosition</code> method on that object is called, which initiates an asynchronous request for the user's position. If the request is successful, the callback function in the method runs. This function accesses the <code>position</code> object's values for latitude and longitude using dot notation and updates the HTML.
</section>

12
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/get-json-with-the-javascript-xmlhttprequest-method.english.md
View File

@ -13,7 +13,17 @@ JSON syntax looks very similar to JavaScript object literal notation. JSON has o
These properties and their values are often referred to as "key-value pairs".
However, JSON transmitted by APIs are sent as <code>bytes</code>, and your application receives it as a <code>string</code>. These can be converted into JavaScript objects, but they are not JavaScript objects by default. The <code>JSON.parse</code> method parses the string and constructs the JavaScript object described by it.
You can request the JSON from freeCodeCamp's Cat Photo API. Here's the code you can put in your click event to do this:
<blockquote>req=new XMLHttpRequest();<br>req.open("GET",'/json/cats.json',true);<br>req.send();<br>req.onload=function(){<br>&nbsp;&nbsp;json=JSON.parse(req.responseText);<br>&nbsp;&nbsp;document.getElementsByClassName('message')[0].innerHTML=JSON.stringify(json);<br>};</blockquote>
```js
req=new XMLHttpRequest();
req.open("GET",'/json/cats.json',true);
req.send();
req.onload=function(){
json=JSON.parse(req.responseText);
document.getElementsByClassName('message')[0].innerHTML=JSON.stringify(json);
};
```
Here's a review of what each piece is doing. The JavaScript <code>XMLHttpRequest</code> object has a number of properties and methods that are used to transfer data. First, an instance of the <code>XMLHttpRequest</code> object is created and saved in the <code>req</code> variable.
Next, the <code>open</code> method initializes a request - this example is requesting data from an API, therefore is a "GET" request. The second argument for <code>open</code> is the URL of the API you are requesting data from. The third argument is a Boolean value where <code>true</code> makes it an asynchronous request.
The <code>send</code> method sends the request. Finally, the <code>onload</code> event handler parses the returned data and applies the <code>JSON.stringify</code> method to convert the JavaScript object into a string. This string is then inserted as the message text.

14
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/handle-click-events-with-javascript-using-the-onclick-property.english.md
View File

@ -7,9 +7,19 @@ challengeType: 6
## Description
<section id='description'>
You want your code to execute only once your page has finished loading. For that purpose, you can attach a JavaScript event to the document called <code>DOMContentLoaded</code>. Here's the code that does this:
<blockquote>document.addEventListener('DOMContentLoaded',function() {<br><br>});</blockquote>
```js
document.addEventListener('DOMContentLoaded',function() {
});
```
You can implement event handlers that go inside of the <code>DOMContentLoaded</code> function. You can implement an <code>onclick</code> event handler which triggers when the user clicks on the element with id <code>getMessage</code>, by adding the following code:
<blockquote>document.getElementById('getMessage').onclick=function(){};</blockquote>
```js
document.getElementById('getMessage').onclick=function(){};
```
</section>
## Instructions

16
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/post-data-with-the-javascript-xmlhttprequest-method.english.md
View File

@ -8,7 +8,21 @@ challengeType: 6
<section id='description'>
In the previous examples, you received data from an external resource. You can also send data to an external resource, as long as that resource supports AJAX requests and you know the URL.
JavaScript's <code>XMLHttpRequest</code> method is also used to post data to a server. Here's an example:
<blockquote>const xhr = new XMLHttpRequest();<br>xhr.open('POST', url, true);<br>xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8');<br>xhr.onreadystatechange = function () {<br>&nbsp;&nbsp;if (xhr.readyState === 4 && xhr.status === 201){<br>&nbsp;&nbsp;&nbsp;&nbsp;const serverResponse = JSON.parse(xhr.response);<br>&nbsp;&nbsp;&nbsp;&nbsp;document.getElementsByClassName('message')[0].textContent = serverResponse.userName + serverResponse.suffix;<br>&nbsp;&nbsp;}<br>};<br>const body = JSON.stringify({ userName: userName, suffix: ' loves cats!' });<br>xhr.send(body);</blockquote>
```js
const xhr = new XMLHttpRequest();
xhr.open('POST', url, true);
xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8');
xhr.onreadystatechange = function () {
if (xhr.readyState === 4 && xhr.status === 201){
const serverResponse = JSON.parse(xhr.response);
document.getElementsByClassName('message')[0].textContent = serverResponse.userName + serverResponse.suffix;
}
};
const body = JSON.stringify({ userName: userName, suffix: ' loves cats!' });
xhr.send(body);
```
You've seen several of these methods before. Here the <code>open</code> method initializes the request as a "POST" to the given URL of the external resource, and uses the <code>true</code> Boolean to make it asynchronous.
The <code>setRequestHeader</code> method sets the value of an HTTP request header, which contains information about the sender and the request. It must be called after the <code>open</code> method, but before the <code>send</code> method. The two parameters are the name of the header and the value to set as the body of that header.
Next, the <code>onreadystatechange</code> event listener handles a change in the state of the request. A <code>readyState</code> of 4 means the operation is complete, and a <code>status</code> of 201 means it was a successful request. The document's HTML can be updated.

8
curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/pre-filter-json-to-get-the-data-you-need.english.md
View File

@ -9,7 +9,13 @@ challengeType: 6
If you don't want to render every cat photo you get from the freeCodeCamp Cat Photo API, you can pre-filter the JSON before looping through it.
Given that the JSON data is stored in an array, you can use the <code>filter</code> method to filter out the cat whose "id" key has a value of 1.
Here's the code to do this:
<blockquote>json = json.filter(function(val) {<br>&nbsp;&nbsp;return (val.id !== 1);<br>});</blockquote>
```js
json = json.filter(function(val) {
return (val.id !== 1);
});
```
</section>
## Instructions