Sending an array of integer values via AJAX post to Flask view - arrays

Question

Suppose you have an array in javascript - [1,2,3] and you want to send it via AJAX post to Flask.
So that in JS:
array = new Array()
array.push(1);
array.push(2);
array.push(3);
var data = JSON.stringify(array);
$.ajax({
type: "POST",
url: "myurl",
data: data,
dataType: 'JSON',
success: alert("messagesent!")
})
And in Flask view :
#bp.route('myurl',methods=['GET', 'POST'])
def myfunction(address):
if request.method == "POST":
FirstSet = request.form['data']
x = json.loads(FirstSet)
However now I dont know how to access the particular values of x list(?), because trying to access it like this :
print(x[1])
does not work...Thanks in advance for looking at it :)
EDIT:
The bigger picture:
I trigger ajax request onclick but after I append all the values that I want to to the array that i want to send. It looks like this:
$("#firstSet").on("click",function(){
array =[]
$("#myDiv").children().each(function()
{
var star = $(this).children("li.star.selected").length
array.push(star)
})
alert(array)
$.ajax({
type: "POST",
url: "myurl",
data: {"data":array},
success: alert("messagesent!")
})
})
This alerted array is not NoneType (and I just get my array values) but what I receive in Flask side is an empty list or NoneType (depenending on how i request it)

Answer 1

Since you're sending JSON you should use Flask to get that JSON with the appropriately named .get_json():
# ...
FirstSet = request.get_json()
Then FirstSet will contain:
[1, 2, 3]
Also ensure your AJAX has the appropriate contentType:
// ...
contentType: "application/json",
dataType: "JSON"
Edit: I'm including all the Javascript/JQuery that I'm testing with in case it helps you. I wrapped everything in a DOM ready function.
<script>
$(document).ready(function() {
$("#firstSet").on("click",function(){
array = [];
var listItems = $("#myDiv li");
listItems.each(function(idx, li) {
var star = $(li);
array.push(star.length);
});
alert(array);
$.ajax({
type: "POST",
url: "/testing",
contentType: "application/json",
dataType: "JSON",
data: JSON.stringify(array)
});
});
});
</script>
And the HTML:
<button id="firstSet" name="firstSet">testing</button>
<div id="myDiv" name="myDiv">
<ul id="myList">
<li data-value="1">1</li>
<li data-value="2">2</li>
<li data-value="3">3</li>
</ul>
<input id="listChoice" size="15" name="size" type="text" />
</div>
And the Flask code:
#bp.route('/testing',methods=["GET","POST",])
def testing():
if request.method == "POST":
print(request.get_json())
return render_template('testing.txt')