CODEWITHSUNDEEP
javascriptjqueryjson
Arkoudinos
Arkoudinos

Reputation: 1128

Cannot read property of undefined after JSON parse

I have done an ajax request in my code and it works good. After that I want to extract only the necessary info and re-post it to another script. Until now here is my code:

$.ajax({
        type: "POST",
                url: url,
                data: {xhr_id: xhr_id},
                success: function (jsondata) {

                    var product_data = [];

                      for (var i = 0; i <= 3; i++) {

                        //alert(jsondata.products[i].product_description.toSource());

                        product_data[i] = {};
                        product_data[i]["product" + i] = jsondata.products[i].product_description;

                        //alert(product_data[i]["product" + i].toSource());
                    }
                },
                dataType: "json"
        });

The problem is that both the alerts work fine, displaying the information I want. However, I get an error message of "Uncaught TypeError: Cannot read property 'product_description' of undefined" which breaks the script and prevents me from doing anything else. What am I doing wrong, any ideas?

Upvotes: 2

Views: 2942

Answers (2)

Vanquished Wombat
Vanquished Wombat

Reputation: 9525

The parameter in the success() function of $.ajax is a string. You have to put it through a parse function to make json. See your code below modified but not tested.

$.ajax({
        type: "POST",
                url: url,
                data: {xhr_id: xhr_id},
                success: function (jsondata) {
                    var oData;
                    try { oData=jQuery.parseJSON(jsondata) }
                    catch(err) {
                        alert("Problem parsing json string : " + jsondata)
                        return false
                    }

                    var product_data = [];

                      for (var i = 0; i <= 3; i++) {

                        //alert(oData.products[i].product_description.toSource());

                        product_data[i] = {};
                        product_data[i]["product" + i] = oData.products[i].product_description;

                        //alert(product_data[i]["product" + i].toSource());
                    }
                },
                dataType: "json"
        });

Upvotes: 0

Ein2012
Ein2012

Reputation: 1103

'product_description' of undefined" what it means is that your are trying to access property on undefined variable. That implies "jsondata.products[i]" resulted in undefined value which have occured due to index out of range.How many records are returned in jsondata 3 or 4,check and adjust the condition in for loop

Upvotes: 2

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