Question 303184 in Jquery Question posted in
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Jquery – javascript not accessing array or object

I’m working on a script that will loop through something similar to the following

$( document ).ready(function() {

  let myObj = {};

  initLoop();

  function initLoop() { //this loads the initial frames into the object
    $('.looper').each(function(i, e){
      var attr1 = $(this).attr('attr1');
      var attr2 = $(this).attr('attr2');
      var attr3 = $(this).attr('attr3');
      var contents = $(this).html();
      myObj[attr1][attr2][attr3] = contents;
    });
  }
});

I’m looping through a set of divs structured like this…

<div class="looper" attr1="1" attr2="1" attr3="1">content</div>
<div class="looper" attr1="1" attr2="1" attr3="2">content</div>
<div class="looper" attr1="1" attr2="1" attr3="3">content</div>
<div class="looper" attr1="1" attr2="2" attr3="1">content</div>
<div class="looper" attr1="1" attr2="2" attr3="2">content</div>
<div class="looper" attr1="1" attr2="2" attr3="3">content</div>
<div class="looper" attr1="1" attr2="3" attr3="1">content</div>
<div class="looper" attr1="1" attr2="3" attr3="2">content</div>
<div class="looper" attr1="1" attr2="3" attr3="3">content</div>

I’m getting the error

jQuery.Deferred exception: Cannot read properties of undefined (reading ‘1’) TypeError: Cannot read properties of undefined (reading ‘1’)

I’m a bit lost on why this isn’t working.
Can anyone suggest any changes?

Tags:

2

Answers


  1. 0

    I think myObj doesn’t have '1' field.

    So, myObj[attr1] is undefined.

    As a result, myObj[attr1][attr2] generate error.

    I add some example code below.

    Hope to help you even a little.

    ...
$(".looper").each(function (i, e) {
  var attr1 = $(this).attr("attr1");
  var attr2 = $(this).attr("attr2");
  var attr3 = $(this).attr("attr3");
  ((myObj[attr1] ??= {})[attr2] ??= {})[attr3] = $(this).html();
});
...
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  2. 0

    It seems like the issue is related to the fact that you are trying to access properties of an object that may not exist yet. Specifically, when you try to access myObj[attr1][attr2][attr3], it’s possible that myObj[attr1] or myObj[attr1][attr2] is undefined.

    To fix this, you need to make sure that each level of the object hierarchy exists before trying to access its properties. Here’s an updated version of your code:

    $(document).ready(function () {
  let myObj = {};

  initLoop();

  function initLoop() {
    $('.looper').each(function (i, e) {
      var attr1 = $(this).attr('attr1');
      var attr2 = $(this).attr('attr2');
      var attr3 = $(this).attr('attr3');
      var contents = $(this).html();

      // Make sure the nested objects exist before assigning values
      myObj[attr1] = myObj[attr1] || {};
      myObj[attr1][attr2] = myObj[attr1][attr2] || {};
      myObj[attr1][attr2][attr3] = contents;
    });
  }
});

    This modification ensures that myObj[attr1] and myObj[attr1][attr2] are initialized as empty objects if they don’t exist yet. That way, you won’t encounter the "Cannot read properties of undefined" error.

    Make sure to adjust this code according to your exact requirements and the structure of your data.

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