Check if a JSON array is empty

Question

I know from the first look it sounds like duplicate question but i don't think it is...

I am receiving back a JSON array as:

var test1 = [] ;

or

var test2 = [{},{},{}] ;  //This is empty

I have no problem finding out if test1 is empty.

jQuery.isEmptyObject(test1)

My problem is with the test2... Please note that in some cases the test2 might return something like:

var test2 = [{"a":1},{},{}] ;  //All these are not empty
var test2 = [{},{"a":1},{}] ;  //All these are not empty
var test2 = [{},{},{"a":1}] ;  //All these are not empty

The above scenarios shouldn't be counted as empty.I've tried to use .length but it's not helping as the length is always 3... Any ideas?

Cheers.

Are you saying that it should only return true if the array is empty or the array only contains objects without keys? — Evan Trimboli
– Evan Trimboli, Commented Aug 23, 2013 at 6:26
Why not just use this if statement: test2[0].length===0&&test[1].length===0&&test[2].length===0 i know it s crude but whatever — markasoftware
– markasoftware, Commented Aug 23, 2013 at 6:30
+1 Evan, if you use .length to an object you will just get an undefined error . @ Evan Trimboli i just need to capture the scenario were test2 is [{},{},{}] — Thanos
– Thanos, Commented Aug 23, 2013 at 6:35

c.P.u1 · Accepted Answer · 2013-08-26 09:09:16Z

7

function isArrayEmpty(array) {
    return array.filter(function(el) {
        return !jQuery.isEmptyObject(el);
    }).length === 0;
}

jsFiddle Demo

Passes all of your tests.

A pure JavaScript solution would be to replace !jQuery.isEmptyObject(el) with Object.keys(el).length !== 0

Edit: Using Array.prototype.every

function isArrayEmpty(array) {
    return array.every(function(el) {
        return jQuery.isEmptyObject(el);
    });
}

edited Aug 26, 2013 at 9:09

answered Aug 23, 2013 at 6:26

c.P.u1

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Comments

Evan Trimboli · Accepted Answer · 2013-08-23 06:39:34Z

For those playing at home, a non jQuery solution:

var test2 = [{a: 1},{},{}] ;  //This is empty

function isEmpty(val) {
    var len = val.length,
        i;

    if (len > 0) {
        for (i = 0; i < len; ++i) {
            if (!emptyObject(val[i])) {
                return false;
            }
        }
    }
    return true;
}

function emptyObject(o) {
    for (var key in o) {
        if (o.hasOwnProperty(key)) {
            return false;
        }
    }
    return true;
}

console.log(isEmpty(test2));

KooiInc · Accepted Answer · 2018-01-19 09:19:42Z

2

Without JQuery: using Array.filter¹ and Object.keys²:

function JSONEmpty(obj){
    return !obj.length || 
           !obj.filter(function(a){return Object.keys(a).length;}).length;
}
// usage
JSONEmpty([{"a":1},{},{}]);  //=> false
JSONEmpty([{},{"a":1},{}]);  //=> false
JSONEmpty([{},{},{"a":1}]);  //=> false
JSONEmpty([]);               //=> true
JSONEmpty([{},{},{}]);       //=> true

update 2018 Arrow functions are now supported by all modern browsers, so like himel-nag-rana stipulated, you can also use:

const JSONEmpty = obj => !obj.length || !obj.filter(a => Object.keys(a).length).length;

¹ More info
² More info (links contain shims for older browsers)

edited Jan 19, 2018 at 9:19

answered Aug 23, 2013 at 6:38

KooiInc

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4 Comments

Evan Trimboli Over a year ago

Probably worth noting the browser compatibility for Object.keys and Array.filter.

Himel Nag Rana Over a year ago

a more shorter version with arrow function isJSONArrayEmpty(obj) { return !obj.length || !obj.filter(a => Object.keys(a).length).length; }

KooiInc Over a year ago

@HimelNagRana I'm pretty sure arrow functions were not or partly implemented in most browsers back in august 2013

Himel Nag Rana Over a year ago

@KooiInc, yes of course that came much later. But my point of adding this was just to add to the solution so that when devs from 2018 comes they get a shorter/updated version. Nothing else. :-)

kunde · Accepted Answer · 2015-05-15 21:18:26Z

1

I had the same problem, and I come with this solution without jQuery:

function isEmpty(x) {
   for(var i in x) {
       return false;
   }
   return true;
}

answered May 15, 2015 at 21:18

kunde

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Comments

Ch33f · Accepted Answer · 2013-08-23 06:38:08Z

0

Pretty simple...

if(jQuery.isEmptyObject(test2[0]) && jQuery.isEmptyObject(test2[1]) && jQuery.isEmptyObject(test2[2])))
    // do something

answered Aug 23, 2013 at 6:38

Ch33f

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2 Comments

Evan Trimboli Over a year ago

What if the array has 4 elements?

Ch33f Over a year ago

Yeah i was lazy but you could very easily implement this in a loop.

Eadel · Accepted Answer · 2013-08-23 06:38:29Z

0

Maybe you could try use function like

function isEmptyObject (test) {
    for (var i in test) {
        if (!jQuery.isEmptyObject(test[i])
            return false;
    }
    return true;
}

answered Aug 23, 2013 at 6:38

Eadel

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Comments

tarikki · Accepted Answer · 2018-02-28 10:06:15Z

0

Here's my take: turn the array into a set and check for size.

var myArray = [1,2,3];
var mySet = new Set(myArray);
console.log(mySet.size === 0);

answered Feb 28, 2018 at 10:06

tarikki

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Comments

Arun Bertil · Accepted Answer · 2013-08-23 06:58:35Z

-1

check by looping each values in array and return error Try

for(i=0;js_array[i]!=null;i++)
{
  if(js_array[i]=="")
  { 
    alert("Empty");
  }
}

edited Aug 23, 2013 at 6:58

answered Aug 23, 2013 at 6:34

Arun Bertil

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1 Comment

Evan Trimboli Over a year ago

This will always return false since the condition is using an assignment to a falsey value.

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