how to find out null values in an object in javascript?

Question

im trying to find a way to alert when there is a null values in an object, if its present it should alert fail and if it doesn't it continues with the another action. Currently im able to alert for each key. with this code:

var ave = {
 'a': '02',
 'b': '04',
 'c': '',
 'd': '',
 'f': '07'
 };

var total = 0
$.each(ave, function(key, value) {
  var numbersA = total + value.length;
    if (numbersA === 0) {
       alert("Fail!");
     } else {
       alert("Pass!");
     }
});

It pops up Fail! twice and Pass 3 times. i want it to alert fail even if there is single null value present in the object. Is there way to do it?

Do you mean if a null (by which you seem to mean any falsy) value is found, the alert should fire and the loop should exit? — Mitya
– Mitya, Commented Jul 4, 2012 at 23:48
Just return false on fail. Btw, '' is not null, 0 is not null, null is null. — elclanrs
– elclanrs, Commented Jul 4, 2012 at 23:49
null !== '' as @elclanrs said. Are you looking for falsy values or just empty strings? — Fabrício Matté
– Fabrício Matté, Commented Jul 4, 2012 at 23:51

Ry- · Accepted Answer · 2012-07-04 23:56:43Z

2

I would use a for in loop; jQuery's jQuery.each isn't well-suited to this situation.

var ave = {
 'a': '02',
 'b': '04',
 'c': '',
 'd': '',
 'f': '07'
};

var success = true;

for(var x in ave) {
    if(ave.hasOwnProperty(x)) {
        if(ave[x] === '') {
            success = false;
            break;
        }
    }
}

if(success) {
    alert('Pass!');
} else {
    alert('Fail!');
}

answered Jul 4, 2012 at 23:56

Ry-♦

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2 Comments

Fabrício Matté Over a year ago

for in is also more well-suited as you can just return false in the scope it belongs to. The success var would be redundant here if you didn't need alerts, unlike $.each which would have a function closure for each key->value iteration (and I've never seen anyone iterating object properties with $.each successfully). +1

The Alpha Over a year ago

I missed but the shortest one.

jeff · Accepted Answer · 2012-07-04 23:54:01Z

Just set a global variable named failed and alter its value if any of the properties are null:

var ave = {
 'a': '02',
 'b': '04',
 'c': '',
 'd': '',
 'f': '07'
 };

var failed = false;
var total = 0;
$.each(ave, function(key, value) {
  var numbersA = total + value.length;
    if (numbersA === 0) {
       failed = true;
    }
});
if (failed)
    alert("Fail!");

Also, note that I'm using your method to check for null values, which is incorrect. If you wanted to actually check for null values, you would changed

if (numbersA === 0) {
    failed = true;
}

to

if (numbersA === null) {
    failed = true;
}

and then, if you wanted ave to fail, you would need to change the empty strings to null as well:

 var ave = {
 'a': '02',
 'b': '04',
 'c': null,
 'd': null,
 'f': '07'
 };

Jérôme · Accepted Answer · 2012-07-05 00:10:33Z

1

You can test the following code here, play with the two sets of data. Note, that the default is 'ave_success', so the alert "Success !" will pop up when you will open the link.

Change "$.each(ave_success" to "$.each(ave_fail" to verify that the wrong data is rejected.

Note that an empty string '' is not considered as null

'' === null

will return false

var ave_fail = {
  'a': '02',
  'b': '04',
  'c': '',
  'd': '',
  'f': '07'
};

var ave_success = {
  'a': '02',
  'b': '04',
  'f': '07'
};

var total = 0
var success = true;

$.each(ave_success, function(key, value) {
  var numbersA = total + value.length;
  if (numbersA === 0) {
    alert("Fail on index " + key + ' !');
    success = false;
    return false;
  }
});

if (success) alert("Success !");

edited Jul 5, 2012 at 0:10

answered Jul 5, 2012 at 0:01

Jérôme

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4 Comments

Ry- Over a year ago

A link is not an answer. Please include your code in your answer.

Fabrício Matté Over a year ago

1. Links are not answers (+1 @minitech). 2. It alerts success when it shouldn't!?

Jérôme Over a year ago

Sorry guys, I won't do it again. @FabrícioMatté, please read my answer concerning 2.

Jérôme Over a year ago

@minitech sorry, answer completed

The Alpha · Accepted Answer · 2012-07-05 00:56:24Z

0

I missed it but the shortest one

var ave = {
  'a': '1',
  'b': '04',
  'c': '4',
  'd': '',
  'f': '1'
};

(function(){
    var v='Success';    
    for(var x in ave) if(!ave[x]) { v='Fail'; break;}
    alert(v);    
})();

DEMO.

OR

function is_falsy(arg){
  var what=true;    
  for(var x in arg) if(!arg[x]) { what=false; break;}
  return what;    
}
alert(is_falsy(ave));

DEMO.

edited Jul 5, 2012 at 0:56

answered Jul 5, 2012 at 0:23

The Alpha

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