What might be causing the hasOwnProperty(key) method in JSON to return false?

Question

What might be causing the hasOwnProperty(key) method in JSON to return false?

I have successfully implemented a method to loop through the JSON data provided below:

{"dummmysetsJSONArr":[{"entryID":"1","distance":"100","calories":"50"},{"entryID":"2","distance":"200","calories":"100"},{"entryID":"3","distance":"300","calories":"150"},{"entryID":"4","distance":"400","calories":"200"},{"entryID":"5","distance":"500","calories":"250"},{"entryID":"6","distance":"600","calories":"300"}],"success":1}

This is how I am achieving this:

    for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
            myLogger(jsonarray[key].entryID + " - " + jsonarray[key].distance + " - " + jsonarray[key].calories);
        }
    }

However, my JSON data seems to be causing an issue with the if check in the for loop.

What might be going wrong with my JSON object?

My intention is to utilize the above for loop to populate data into google.visualization.DataTable() as shown below:

        data = new google.visualization.DataTable();
        data.addColumn('number', 'distance');
        data.addColumn('number', 'calories');

        for (var key in obj) {
            if (obj.hasOwnProperty(key)) {

                //data.addRow(jsonarray[key].distance);
                //data.addRow(jsonarray[key].calories);
            }
        }

javascript json

Answer 1

Answer №1

If you are looking for a specific property in a collection, you can use the following code snippet (view example on jsbin):

var obj = {"dummmysetsJSONArr":[{"entryID":"1","distance":"100","calories":"50"},{"entryID":"2","distance":"200","calories":"100"},{"entryID":"3","distance":"300","calories":"150"},{"entryID":"4","distance":"400","calories":"200"},{"entryID":"5","distance":"500","calories":"250"},{"entryID":"6","distance":"600","calories":"300"}],"success":1};

for (var key in obj.dummmysetsJSONArr) {
    if (obj.dummmysetsJSONArr.hasOwnProperty(key)) {
        document.write(obj.dummmysetsJSONArr[key].distance + " " + obj.dummmysetsJSONArr[key].calories);              
        document.write("<br/>");
    }
}

Alternatively, you can search for objects that have specific properties like entryId, distance, and calories to account for any potential variability in your JSON structure.

Answer 2

If you are looking for a specific property in a collection, you can use the following code snippet (view example on jsbin):

var obj = {"dummmysetsJSONArr":[{"entryID":"1","distance":"100","calories":"50"},{"entryID":"2","distance":"200","calories":"100"},{"entryID":"3","distance":"300","calories":"150"},{"entryID":"4","distance":"400","calories":"200"},{"entryID":"5","distance":"500","calories":"250"},{"entryID":"6","distance":"600","calories":"300"}],"success":1};

for (var key in obj.dummmysetsJSONArr) {
    if (obj.dummmysetsJSONArr.hasOwnProperty(key)) {
        document.write(obj.dummmysetsJSONArr[key].distance + " " + obj.dummmysetsJSONArr[key].calories);              
        document.write("<br/>");
    }
}

Alternatively, you can search for objects that have specific properties like entryId, distance, and calories to account for any potential variability in your JSON structure.

Answer 3

Answer №2

It seems that you require several rounds of going through key/value pairs. During the initial iteration, you will retrieve the key 'dummmysetsJSONArr' along with an array as its value.

Subsequently, you will iterate through the array where each key represents the index and the value signifies the object.

Further traversal through the value will provide you with the attribute name of the object and its corresponding value.

Answer 4

It seems that you require several rounds of going through key/value pairs. During the initial iteration, you will retrieve the key 'dummmysetsJSONArr' along with an array as its value.

Subsequently, you will iterate through the array where each key represents the index and the value signifies the object.

Further traversal through the value will provide you with the attribute name of the object and its corresponding value.

Answer 5

Answer №3

To access the "dummmysetsJSONArr" property which is an array and not an object, you can use the following code:

var myObj = {"dummmysetsJSONArr":[{"entryID":"1","distance":"100","calories":"50"},{"entryID":"2","distance":"200","calories":"100"},{"entryID":"3","distance":"300","calories":"150"},{"entryID":"4","distance":"400","calories":"200"},{"entryID":"5","distance":"500","calories":"250"},{"entryID":"6","distance":"600","calories":"300"}],"success":1}
var obj = myObj.dummmysetsJSONArr; //this is an array not an object
var str = "";
for (var i=0;i< obj.length;i++) {     
    str += obj[i].entryID + " - " + obj[i].distance + " - " + obj[i].calories+"<br>";
}

Alternatively, as arrays in JavaScript are objects with numerical keys, you can also access it like this:

var obj = myObj.dummmysetsJSONArr; //this is an array not an object
var str = "";
 for (key in obj) {     
            str += obj[key].entryID + " - " + obj[key].distance + " - " + obj[key].calories+"<br>";
    }

It is not necessary to check for hasOwnProperty since each property in your JSON object is its own property.

Answer 6

To access the "dummmysetsJSONArr" property which is an array and not an object, you can use the following code:

var myObj = {"dummmysetsJSONArr":[{"entryID":"1","distance":"100","calories":"50"},{"entryID":"2","distance":"200","calories":"100"},{"entryID":"3","distance":"300","calories":"150"},{"entryID":"4","distance":"400","calories":"200"},{"entryID":"5","distance":"500","calories":"250"},{"entryID":"6","distance":"600","calories":"300"}],"success":1}
var obj = myObj.dummmysetsJSONArr; //this is an array not an object
var str = "";
for (var i=0;i< obj.length;i++) {     
    str += obj[i].entryID + " - " + obj[i].distance + " - " + obj[i].calories+"<br>";
}

Alternatively, as arrays in JavaScript are objects with numerical keys, you can also access it like this:

var obj = myObj.dummmysetsJSONArr; //this is an array not an object
var str = "";
 for (key in obj) {     
            str += obj[key].entryID + " - " + obj[key].distance + " - " + obj[key].calories+"<br>";
    }

It is not necessary to check for hasOwnProperty since each property in your JSON object is its own property.

What might be causing the hasOwnProperty(key) method in JSON to return false?

Answer №1

Answer №2

Answer №3

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