javascript - get the position in a table

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I have this .I am able to drag where ever I want.Is there a way to create another table that I will get the positions of each image where it goes?(only the position).An example,as you can see there are positions 1 until 24.In position 12 I have red images.In position 24 I have black images.What I was to do is if I drag from position 12 the image with number a to the position,I want to put this value lets say in the slot 11, then when I did that drag it will be creating a new table like and will write (11,a).Conclusion, 11 will be the position and a the image i transfer.Can that happen?I am trying so far with not a result..thanks in advance.

edited: you drag an image in position lets say 5,a next drag you do with the same image you go to (1,a ) then you can not drag anymore that image -(if that can happen )

Answer

Solution:

It's much easier when you decouple the data from the UI - meaning that a dataset is being processed in the background while the images are dragged around.

In the following little snippet I'll attempt to do that with your case. The items keep track if they can be dragged or not.

The items are now filled with only 4 images, but you can add any number of images there - they can be handled as separate items. The only thing to pay attention to: the ids of the items must be unique.

const items = [{
    id: 0,
    dataid: "a",
    type: "red",
    src: "https://i.imgur.com/ZEZLSOo.png",
    draggable: 2,
    position: 12,
    alt: "Norway",
  },
  {
    id: 1,
    dataid: "b",
    type: "red",
    src: "https://i.imgur.com/ZEZLSOo.png",
    draggable: 2,
    position: 12,
    alt: "Norway",
  },
  {
    id: 2,
    dataid: "a",
    type: "black",
    src: "https://i.imgur.com/dL3J8XS.jpeg",
    draggable: 2,
    position: 13,
    alt: "Norway",
  },
  {
    id: 3,
    dataid: "b",
    type: "black",
    src: "https://i.imgur.com/dL3J8XS.jpeg",
    draggable: 2,
    position: 13,
    alt: "Norway",
  }
]

const itemHTML = (item) => {
  return `
    <span
      class="event"
      data-id="${ item.dataid }"
      draggable="${ !!item.draggable }"
    >
     ${ item.dataid } <img
        data-imgid="${ item.id }"
        src="${ item.src }"
        class="b"
        alt="${ item.alt }"
        style="width: 30%;"
      />
    </span>
  `
}

// redrawing the table based on item attributes
const updateTable = (table, items) => {
  $(table).find('td').each(function(i, e) {
    let html = ''
    const filtered = items.filter(({
      position
    }) => position - 1 === i)
    if (filtered.length) {
      filtered.forEach(item => {
        html += itemHTML(item)
      })
    } else {
      html = !$(e).parent().index() ? i + 1 : 24 - $(e).index()
    }
    e.innerHTML = html
  })
}

updateTable('#targetTable tbody', items)

const dragrowHTML = ({
  id,
  to
}) => {
  return `<tr><td>${ id }</td><td>${ to }</td></tr>`
}

$(function() {
  initDragAndDrop();
});

function clearDragAndDrop() {
  $('.event').off();
  $('#targetTable td').off('dragenter dragover drop');
}

function initDragAndDrop() {
  $('.event').on('dragstart', function(event) {
    const itemid = event.target.getAttribute('data-imgid')
    var dt = event.originalEvent.dataTransfer;
    //add dat-attr and class from where to remove
    dt.setData('id', itemid);
  });

  $('.event').on('dragend', function(event) {
    clearDragAndDrop();
    initDragAndDrop();
  });

  // updated event handling
  $('#targetTable td').on('dragenter dragover drop', function(event) {
    event.preventDefault();
    if (event.type === 'drop') {
      const itemid = event.originalEvent.dataTransfer.getData('id');
      const item = items.find(({
        id
      }) => id == itemid)
      // if item is draggable
      if (item && item.draggable) {
        // calculate position
        item.position = ($(event.target).parent().index() * $(event.target).parent().children().length) + ($(event.target).index() + 1)
        // update table
        updateTable('#targetTable tbody', items)
        // update item's draggable property
        $('#dragtable tbody').append(dragrowHTML({
          id: item.id,
          to: item.position
        }))
        item.draggable--
      }
    }
  });
}

html,
body {
  margin: 0;
}

table {
  border-collapse: collapse;
}

td span {
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #09C;
  font-weight: bold;
}

img {
  padding: 10px;
}

#dragtable {
  border-collapse: collapse;
}

#dragtable th,
#dragtable td {
  border: 1px solid black;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<table id="targetTable" class="b" border="10" bordercolor="blue" id="myT">
  <tbody>
    <tr>
      <td> 1</td>
      <td> 2</td>
      <td> 3</td>
      <td> 4</td>
      <td> 5</td>
      <td> 6</td>
      <td> 7</td>
      <td> 8</td>
      <td> 9</td>
      <td> 10</td>
      <td> 11</td>
      <td> 12</td>
    </tr>
    <tr>
      <td> 24</td>
      <td> 23</td>
      <td> 22</td>
      <td> 21</td>
      <td> 20</td>
      <td> 19</td>
      <td> 18</td>
      <td> 17</td>
      <td> 16</td>
      <td> 15</td>
      <td> 14</td>
      <td> 13</td>
    </tr>
  </tbody>
</table>

<table id="dragtable">
  <thead>
    <tr>
      <td>ID</td>
      <td>TO</td>
    </tr>
  </thead>
  <tbody>
  </tbody>
</table>

Source