DataTables: Cannot read property 'length'

Question

I understand this a popular issue, and I have read all the similar questions here on Stack Overflow and other sites (including the datatables website).

To clarify, I am using

• PHP Codeigniter
• Materliazecss

I have also made sure that I received the JSON array correctly:

[{"name_en":"hello","phone":"55555555"},{"name_en":"hi","phone":"00000000"}]

My HTML table looks like this:

<table id="customer_table">
     <thead>
         <tr>
            <th>Name</th>
            <th>Phone</th>
         </tr>
     </thead>
</table>

And here is my document.ready function:

  $(document).ready(function(){
            //$('#customer_table').DataTable();
            $('#customer_table').DataTable( {
                "ajax": 'json',
                "dataSrc": "",
                 "columns": [
                    { "data": "email" },
                    { "data": "name_en" }
                ]
            });
  });

The error I am getting is

Uncaught TypeError: Cannot read property 'length' of undefined

Answer 1

CAUSE

This errors TypeError: Cannot read property 'length' of undefined usually means that jQuery DataTables cannot find the data in the response to the Ajax request.

By default jQuery DataTables expects the data to be in one of the formats shown below. Error occurs because data is returned in the format other than default.

Array of arrays

{ 
   "data": [
      [
         "Tiger Nixon",
         "System Architect",
         "$320,800",
         "2011/04/25",
         "Edinburgh",
         "5421"
      ]
   ]
}

Array of objects

{ 
   "data": [
      {
         "name": "Tiger Nixon",
         "position": "System Architect",
         "salary": "$320,800",
         "start_date": "2011/04/25",
         "office": "Edinburgh",
         "extn": "5421"
      }
   ]
}

SOLUTION

Use default format or use ajax.dataSrc option to define data property containing table data in Ajax response (data by default).

See Data array location for more information.

LINKS

See jQuery DataTables: Common JavaScript console errors for more details.

Answer 2

When you have JSON data then the following error appears

A better solution is to assign a var data for the local json array object, details see: https://datatables.net/manual/tech-notes/4

This is helps you to display table contents.

 $(document).ready(function(){   

        $('#customer_table').DataTable( {
         "aaData": data,

           "aoColumns": [{
                            "mDataProp": "name_en"
                        }, {
                            "mDataProp": "phone"
                        }, {
                            "mDataProp": "email"
                        }, {
                            "mDataProp": "facebook"
                        }]
            });
        });