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how to form an array of arrays with data

Time:11-30

I need to create an array of arrays like this:

var serviceCoors = [
        [50, 40],
        [50, 50],
        [50, 60],
    ];

from elements with datas:

<div data-latitude="10" data-longitude="20" class="service-points__map"></div>
<div data-latitude="20" data-longitude="10" class="service-points__map"></div>

I`m trying this:

var test = [];
$('.service-points__map').each(function(){
        var test2 = $(this).contents();
        var items = [];
        $.each(test2, function(i, val) {
            items.push(val.data);
        });
        test.push(items);
    });

But it doesn`t work. I have 2 arrays, but they are empty.

CodePudding user response:

Oh, what you did is... var test2 = $(this).contents(); is not the right thing you need to use. You should be using .data() and destructure the object:

var test = [];
$('.service-points__map').each(function() {
  var { longitude, latitude } = $(this).data();
  test.push([longitude, latitude]);
});
console.log(test);
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div data-latitude="10" data-longitude="20" class="service-points__map"></div>
<div data-latitude="20" data-longitude="10" class="service-points__map"></div>
<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

I got the output as:

[
  [ 20, 10 ],
  [ 10, 20 ]
]

CodePudding user response:

Initially I was going to suggest jQuery's map method but - by design apparently - it automatically flattens the output which can only be solved by nesting your coordinates in another array. It also seems like it automatically coerces strings to numbers which is useful in your case but it seems to be making a lot of decisions that you might not want.

const out = $('div').map((i, el) => {
  const { latitude, longitude } = $(el).data();
  return [[ latitude, longitude ]];
}).toArray();

console.log(out);
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div data-latitude="10" data-longitude="20" class="service-points__map"></div>
<div data-latitude="20" data-longitude="10" class="service-points__map"></div>
<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

Native JS doesn't have this problem. Just pick up the elements, and iterate over them returning the new array of nested coordinates.

const divs = document.querySelectorAll('div');

const coords = Array.from(divs).map(div => {
  const { latitude, longitude } = div.dataset;
  return [  latitude,  longitude ];
});

console.log(coords);
<div data-latitude="10" data-longitude="20" class="service-points__map"></div>
<div data-latitude="20" data-longitude="10" class="service-points__map"></div>
<iframe name="sif3" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

Additional documentation

CodePudding user response:

Alternatively, you can use plain JS instead of jQuery. All you need to do is to get elements, iterate over them, create an array of the attributes of each item, and push it into the test array.

const test = [];
const items = document.querySelectorAll('.service-points__map');
items.forEach(item => {
  test.push([
    parseInt(item.getAttribute('data-latitude')),
    parseInt(item.getAttribute('data-longitude')),
  ]);
});

console.log(test);
<div data-latitude="10" data-longitude="20" class="service-points__map"></div>
<div data-latitude="20" data-longitude="10" class="service-points__map"></div>
<iframe name="sif4" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

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