The error

"Uncaught TypeError: Cannot use 'in' operator to search for 'length' in"

is showing in Google chrome console

$(document).ready(function() {
  $("#trackerid").change(function() {
    var var_locoid = $("#trackerid option:selected").val();
    //  alert(var_locoid);
    $("#deliverylocation").autoplete({

      source: function(request, response) {
        var auto_data = $("#deliverylocation").val();
        // alert(auto_data);

        //alert(var_locoid);
        $.ajax({
          url: "http://localhost/CodeProject/Testctrl/lookup",
          type: "POST",
          datatype: "json",
          //returnType:"json",
          data: {
            'var_locoid': var_locoid,
            'auto_data': auto_data
          },
          success: function(data) {
            var resp = $.map(data, function(obj) {
              return obj.tag;
            });

            response(resp);
          }
        });
      },
      minLength: 1
    });
  });
});

<script src=".1.1/jquery.min.js"></script>

The error

"Uncaught TypeError: Cannot use 'in' operator to search for 'length' in"

is showing in Google chrome console

$(document).ready(function() {
  $("#trackerid").change(function() {
    var var_locoid = $("#trackerid option:selected").val();
    //  alert(var_locoid);
    $("#deliverylocation").autoplete({

      source: function(request, response) {
        var auto_data = $("#deliverylocation").val();
        // alert(auto_data);

        //alert(var_locoid);
        $.ajax({
          url: "http://localhost/CodeProject/Testctrl/lookup",
          type: "POST",
          datatype: "json",
          //returnType:"json",
          data: {
            'var_locoid': var_locoid,
            'auto_data': auto_data
          },
          success: function(data) {
            var resp = $.map(data, function(obj) {
              return obj.tag;
            });

            response(resp);
          }
        });
      },
      minLength: 1
    });
  });
});

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>

• javascript
• jquery
• codeigniter

• Try alert(data); at the top of your success function to verify what data you get back. – Anthony McGrath Commented Jan 23, 2018 at 6:09
• The in operator only works on objects. You are using it on a string. Make sure your value is an object before you using $.map. I believe, in your case, you will have to parse data before using in $.map... JSON.parse() – Milan Chheda Commented Jan 23, 2018 at 6:09

2 Answers 2

Try this

jQuery.parseJSON(data);

The in operator only works on objects. You are using it on a string. Make sure your value is an object before you using $.map. In this specific case, you have to parse the JSON:

$.map(JSON.parse(data), ...);