JSON has many empty values, where I want to replace the empty value with a default string.

var json= [
{
    "machineNum": "1A",
    "serialNo": "123",
    "city": ""
},
{
    "machineNum": "2B",
    "serialNo": "",
    "city": ""
},
{
    "machineNum": "3A",
    "serialNo": "123",
    "city": "NewCity"
}
]

 var newJson=json.replace("","Not AVailable");
 console.log(newJson);

So wherever there is "" - empty value replace with default value "Not Available"

The above is not working.

JSFIDDLE here

JSON has many empty values, where I want to replace the empty value with a default string.

var json= [
{
    "machineNum": "1A",
    "serialNo": "123",
    "city": ""
},
{
    "machineNum": "2B",
    "serialNo": "",
    "city": ""
},
{
    "machineNum": "3A",
    "serialNo": "123",
    "city": "NewCity"
}
]

 var newJson=json.replace("","Not AVailable");
 console.log(newJson);

So wherever there is "" - empty value replace with default value "Not Available"

The above is not working.

JSFIDDLE here

• javascript
• jquery
• json

• It could work if you used it on the JSON string, and not the parsed JSON object. – doldt Commented Jul 2, 2015 at 12:32

3 Answers 3

You need to do a replace on the json string not a javascript object. Also you aren't looking for "" you are looking for "\"\"":

var json= [
{
    "machineNum": "1A",
    "serialNo": "123",
    "city": ""
},
{
    "machineNum": "2B",
    "serialNo": "",
    "city": ""
},
{
    "machineNum": "3A",
    "serialNo": "123",
    "city": "NewCity"
}
]
var temp = JSON.stringify(json);
temp = temp.replace(/\"\"/g, "\"Not Available\"");
json = JSON.parse(temp);
console.log(json);

Console Output:

If you don't want to stringify/reparse the json, you could loop over the array and each property of the objects in the array.

json.forEach(function (machine) {
    Object.keys(machine).forEach(function (key) {
        if (machine[key] === '' && machine.hasOwnProperty(key)) machine[key] = 'Not Available';
    });
});

You can use Array.prototype.map along with Object.keys to make sure all key-value pairs which have empty value are all applied with default string. See a quick example below:

function replaceEmpty(json, defaultStr){
    return json.map(function (el){
        Object.keys(el).forEach(function(key){
            el[key] = el[key] || defaultStr;
        });
        return el;
    });
}

var result = replaceEmpty(json,"Not Available");

Output

[{"machineNum":"1A","serialNo":"123","city":"Not Available"},{"machineNum":"2B","serialNo":"Not Available","city":"Not Available"},{"machineNum":"3A","serialNo":"123","city":"NewCity"}]