Hashtable functionality using objects in JavaScript

Question

Okay, I have the following scenario: I get an object, which is an array with lists. There is always 3 items in the array.

The items inside the lists, has a specific field I am interested in (ISBN13).

I want to build a table like this using JavaScript:

<table>
    <tr>
        <td>Array_1_Item_1_ISBN13</td>
        <td>Array_2_Item_1_ISBN13</td>
        <td>Array_3_Item_1_ISBN13</td>
    </tr>
    <tr>
        <td>Array_1_Item_2_ISBN13</td>
        <td>Array_2_Item_2_ISBN13</td>
        <td>Array_3_Item_2_ISBN13</td>
    </tr>
</table>

In C#, I would just build a dictionary, and:

• If I've seen the key before, add a new key
• If I have seen the key before, continue building the string

But now I am in jQuery/JS land, and meh.

Below, I have tried to create an object, I use to fill data in. This code have the following issues:

• Instead of adding an entry to the object at key isbn13, it adds object.isbn = ...

• Not sure if the if() statement works

  function setBookTableFromProducts(data) {
  var outputArray = {};
  
  // list is an array of books, e-books and audiobooks)
  $.each($.parseJSON(data), function (index, value) {
      // single type of book
      $.each(value, function (index_inner, book) {
          var isbn13 = book.ISBN13;
          if (outputArray.isbn13 == null) {
              var newRowStr = '<tr>';
              newRowStr += '<td>' + book.ISBN13 + '</td>';
              outputArray.isbn13 = newRowStr;
          } else {
              outputArray.isbn13 += '<td>' +book.ISBN13+ '</td>';
          }
  
      });
  });
  
  $.each(outputArray, function (index, trArr) {
      trArr += '</tr>';
      $('#bookTable').append(trArr);
  });
  

  }

How would you solve this issue? What is wrong with my code? (Oh, and performance doesn't matter)

Answer 1

It would help if you provided an example of the input (i.e. $.parseJSON(data)) or maybe created a jsFiddle.

But one possible issue is outputArray.isbn13. You have var isbn13 = book.ISBN13 take some ISBN value (say 9783161484100) then expect to use it as a key to the outputArray object with outputArray.isbn13. However, the key is isbn13 and not outputArray.9783161484100. Instead, try

var isbn13 = book.ISBN13;
if (outputArray[isbn13] == null) {
  ...
}

This will then get interpreted as outputArray.9783161484100.