如果项目存在于该索引位置,如何更新javascript数组？

Question

jQuery和JavaScript相当新鲜,所以请温柔......

我正在开发一个POC来创建一个"列映射"页面,用户可以将"列标题"列表拖放到新列标题的网格中.我需要构建一个可以发送回SQL数据库的数组.我有这个部分(大部分)按照我的意愿运作.

当项目从左侧的列列表拖动到右侧的标题网格时,如果该项目存在,则代码应更新/替换该索引处的数组项目.如果该项不存在,则应将该项添加到数组中.

例如:如果将"First Name"拖动到"Headers",则应将其添加到索引位置0.如果然后将"First Name"拖动到"with",则应删除索引0处的"First Name"值并添加位置1的值.如果然后将"Last Name"拖动到"with",它应该使用"Last Name"值更新位置1的数组.

$(document).ready(() => {
  $(function() {
    $('.item').draggable({
      cursor: "crosshair",
      cursorAt: {
        left: 5
      },
      distance: 10,
      opacity: 0.75,
      revert: true,
      snap: ".target",
      containment: "window"
    });
  });

  $(function() {
    var array = [];
    var arraytext = '';
    $('.target').droppable({
      accept: ".item",
      tolerance: 'pointer',
      activeClass: 'active',
      hoverClass: 'highlight',
      drop: function(event, ui) {
        var dropped = $(this);
        var dragged = $(ui.draggable);
        $(function(index, item) {
          var test = '';
          array.push($(dragged).text());
          arraytext = JSON.stringify(array);
          test += "Index Value = " + $(dropped).index() + ", Text = " + $(dragged).text() + "<br/>";
          $('#test').html(test);
          $('#array').text(arraytext);
        });
      }
    });
  });
});

#container {
  border: solid black 1px;
  margin: 0 auto;
  height: 800px;
}

#gridview {
  border: 2px solid #292da0;
  border-radius: 5px;
  background-color: #7577a3;
  display: grid;
  grid-template-columns: repeat(auto-fit, 100px);
  grid-template-rows: auto;
  margin-left: 105px;
}

.target {
  border: 2px solid #1c1c3a;
  border-radius: 5px;
  background-color: #a7a7ef;
  padding: 1em;
}

#flex {
  border: 2px solid #292da0;
  border-radius: 5px;
  width: 100px;
  background-color: #7577a3;
  display: flex;
  flex-flow: column wrap;
  justify-content: flex-end;
  float: left;
}

.item {
  border: 2px solid #1c1c3a;
  border-radius: 5px;
  background-color: #a7a7ef;
  padding: 1em;
}

.active {
  background-color: blue;
  color: white;
  border: 2px solid black;
}

.highlight {
  background-color: yellow;
  color: black;
  border: 2px solid blue;
}

.table {
  border: solid black 1px;
  width: 86px;
  padding: 5px;
}

<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script src="https://code.jquery.com/ui/1.12.0/jquery-ui.min.js"></script>
<div id="container">
  Test:
  <div id="test">
  </div>
  Array:
  <div id="array">
  </div>
  <div id="gridview">
    <div class="target">Headers</div>
    <div class="target">with</div>
    <div class="target">different</div>
    <div class="target">column</div>
    <div class="target">names</div>
  </div>
  <span>
  <div id="flex">
    <div class="item">First Name</div>
    <div class="item">Last Name</div>
    <div class="item">Code</div>
    <div class="item">Date</div>
    <div class="item">Amount</div>
  </div>
   <table>
     <thead>
       <tr>
         <td class="table">Some</td>
         <td class="table">Column</td>
         <td class="table">Data</td>
         <td class="table">Goes</td>
         <td class="table">Here</td>
         </tr>
     </thead>
       <tr>
         <td class="table">Other Data</td>
         <td class="table">Other Data</td>
         <td class="table">Other Data</td>
         <td class="table">Other Data</td>
         <td class="table">Other Data</td>
       </tr>
   </table>
  </span>
</div>

JSFiddle:https://jsfiddle.net/qxwzcn9w/4/

最后,如果您发现任何红旗或"陷阱",我会将索引值发送回数据库,以便获得奖励积分.谢谢!

Answer 1

使用 for 循环查找元素是否存在的简单解决方案。$.each()如果您熟悉 jQuery，也可以使用。如果需要，您可以通过计算表头列来计算数组长度$("thead").find("td")。然后照常迭代以查看该元素是否存在，如果存在则将其删除，然后插入到适当的索引中。

$(function() {
  $('.item').draggable({
    cursor: "crosshair",
    cursorAt: {
      left: 5
    },
    distance: 10,
    opacity: 0.75,
    revert: true,
    snap: ".target",
    containment: "window"
  });
});

$(function() {
  var arraytext = '';
  $('.target').droppable({
    accept: ".item",
    tolerance: 'pointer', 
    activeClass: 'active',
    hoverClass: 'highlight',
    drop: function(event, ui) {
      var dropped = $(this);
      var dragged = $(ui.draggable);
      $(function(index, item) {
        var test = '';

        for(var i = 0; i < array.length; i++)
        {
          if($(dragged).text() == array[i])
          {
            array[i] = "";
          }
        }
        array[$(dropped).index()] = $(dragged).text();
        arraytext = JSON.stringify(array);
        test += "Index Value = " + $(dropped).index() + ", Text = " + $(dragged).text() + "<br/>";
        $('#test').html(test);
        $('#array').text(arraytext);
      });
    }
  });
});