Javascript If condition to check a variable with empty object or not

Question

I have a variable var a = {};

if ( a !==null) {
// Entering here if var a has empty object but i don't want to enter.
}

if (a == null) {
// Want to enter into this condition if var a has empty object.
}

I have tried several ways to write this condition like giving a=={} but it still entering first condition. Could you please let me know the appropriate way to check that condition?

Thank you all for your valid responses. @Janaka dissanayake response came handy. — suman
– suman, Commented Nov 11, 2016 at 3:00

Janaka Dissanayake · Accepted Answer · 2016-11-11 01:50:01Z

3

First option

var a = null;

Second option

if ( a !==null && JSON.stringify(a) !== '{}') {..}

answered Nov 11, 2016 at 1:50

Janaka Dissanayake

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1 Comment

Janaka Dissanayake Over a year ago

const empty = {} Object.keys(empty).length === 0 && empty.constructor === Object

Ruan Mendes · Accepted Answer · 2016-11-11 01:43:34Z

2

function isEmptyObject(obj) {
  return Object.keys(obj).length == 0;
}

var a = {};

if (isEmptyObject(a)) {
  console.log('emptyOject')
}

answered Nov 11, 2016 at 1:43

Ruan Mendes

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2 Comments

Will Over a year ago

What if a is null or undefined? Should test for it in function.

Ruan Mendes Over a year ago

@will Not in a function called isEmptyObject, if you change it to isNullOrEmptyObject() then maybe, but the OP 's example is about an empty object. I have a variable var a = {}; In any case, that's trivial... I'm sure the OP can figure that out.

adeneo · Accepted Answer · 2016-11-11 01:50:32Z

1

jQuery does

function isEmptyObject(obj) {
    var name;
    for (name in obj) {
        return false;
    }
    return true;
}

answered Nov 11, 2016 at 1:50

adeneo

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1 Comment

Ruan Mendes Over a year ago

That's going to check inherited properties too. As long as the OP understands and chooses the one they want.

Shravan Ramamurthy · Accepted Answer · 2016-11-11 01:57:07Z

0

In ECMA script 5

var objInTest = {};

function isEmpty(obj) {
    return Object.keys(obj).length === 0;
}

Pre ECMA script 5

function isEmpty(obj) {
    for(var prop in obj) {
        if(obj.hasOwnProperty(prop))
            return false;
    }
    return true;
}

answered Nov 11, 2016 at 1:57

Shravan Ramamurthy

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