Check if item from JSON object is missing

Question

I thought I could do the following to check if a data value was null and then substitute something else.

$.ajax({
    url: 'php/parsedjson.php',
    dataType: 'json',
    success: function(data) {
        $.each(data, function(index, val) {
            if (data[index].Manufacturers[0].Name != null){
             var manufacturer = data[index].Manufacturers[0].Name;}
             else{ var manufacturer ="MISSING"}
        });
    }
})

However, this throws an error Uncaught TypeError: Cannot read property 'Name' of undefined when the data value is not supplied in the JSON.

How do you check if there is a value to prevent this from happening?

JSON is a *textual notation* for data exchange. [(More.)](http://stackoverflow.com/a/2904181/157247) If you're dealing with JavaScript source code, and not dealing with a *string*, you're not dealing with JSON. — T.J. Crowder, Mar 08 '17 at 14:34
@T.J.Crowder Not sure what you mean, the data returned from my PHP is definitely in JSON format. — jonmrich, Mar 08 '17 at 14:36
[i think is a duplicate](http://stackoverflow.com/questions/12770393/javascript-check-if-null-from-json). I hope i helped you — theodosis, Mar 08 '17 at 14:38
@jonmrich: Yes, but that's not what you're dealing with. You're dealing with the result of *parsing* that JSON. It's not JSON anymore. It's just JavaScript objects. — T.J. Crowder, Mar 08 '17 at 14:39

score 1 · Accepted Answer · answered Mar 08 '17 at 14:35

Should be easy:

$.ajax({
    url: 'php/parsedjson.php',
    dataType: 'json',
    success: function(data) {
        $.each(data, function(index, val) {
            if (data[index].Manufacturers[0] && data[index].Manufacturers[0].Name){
             var manufacturer = data[index].Manufacturers[0].Name;}
             else{ var manufacturer ="MISSING"}
        });
    }
});

You have to check also data[index].Manufacturers[0] before getting to name, to avoid null pointers.

Perfect! I'll accept the answer when I'm allowed. Thanks! – jonmrich Mar 08 '17 at 14:39 — jonmrich, Mar 08 '17 at 14:39

Check if item from JSON object is missing

1 Answers1