Is object empty? [duplicate]

Answer 1

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

Answer 2

It might be a bit hacky. You can try this.

if (JSON.stringify(data).length === 2) {
   // Do something
}

Not sure if there is any disadvantage of this method.

Answer 3

var x= {}
var y= {x:'hi'}
console.log(Object.keys(x).length===0)
console.log(Object.keys(y).length===0)

true
false

http://jsfiddle.net/j7ona6hz/1/

Answer 4

https://lodash.com/docs#isEmpty comes in pretty handy:

_.isEmpty({})   // true
_.isEmpty()     // true
_.isEmpty(null) // true
_.isEmpty("")   // true

Answer 5

I'm assuming that by empty you mean "has no properties of its own".

// Speed up calls to hasOwnProperty
var hasOwnProperty = Object.prototype.hasOwnProperty;

function isEmpty(obj) {

    // null and undefined are "empty"
    if (obj == null) return true;

    // Assume if it has a length property with a non-zero value
    // that that property is correct.
    if (obj.length > 0)    return false;
    if (obj.length === 0)  return true;

    // If it isn't an object at this point
    // it is empty, but it can't be anything *but* empty
    // Is it empty?  Depends on your application.
    if (typeof obj !== "object") return true;

    // Otherwise, does it have any properties of its own?
    // Note that this doesn't handle
    // toString and valueOf enumeration bugs in IE < 9
    for (var key in obj) {
        if (hasOwnProperty.call(obj, key)) return false;
    }

    return true;
}

Examples:

isEmpty(""), // true
isEmpty(33), // true (arguably could be a TypeError)
isEmpty([]), // true
isEmpty({}), // true
isEmpty({length: 0, custom_property: []}), // true

isEmpty("Hello"), // false
isEmpty([1,2,3]), // false
isEmpty({test: 1}), // false
isEmpty({length: 3, custom_property: [1,2,3]}) // false

If you only need to handle ECMAScript5 browsers, you can use Object.getOwnPropertyNames instead of the hasOwnProperty loop:

if (Object.getOwnPropertyNames(obj).length > 0) return false;

This will ensure that even if the object only has non-enumerable properties isEmpty will still give you the correct results.

Answer 6

May be you can use this decision:

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