What better way to check if an object is empty?

Question

I have the following object:

let obj = {};

If I try to validate obj.length return me a undefined, then I resorted to the Object.Keys alternative.. Object.keys(obj).length.. solved my problem.. but I wonder if there are any alternatives to this? some native javascript function.. sei la!

Thank you!

Answer 1

You can create a function that will traverse the properties of the object and return the answer.
If the is precorra some property of the object, so it is not empty, it will return false. If he doesn’t go through the go, he will return true
There is an example of code below:

function objIsEmpty(obj) {
  for (let prop in obj) {return false}
  return true;
}

const obj = {'id': 1};
const obj2 = {};
const obj3 = new Object(); // obj vazio
const obj4 = {};
obj4.id = 2;
obj4.nome = 'Teste';

console.log(objIsEmpty(obj), obj);
console.log(objIsEmpty(obj2), obj2);
console.log(objIsEmpty(obj3), obj3);
console.log(objIsEmpty(obj4), obj4);

See if that suits you. Any questions, just talk.

Answer 2

For this case, it can be checked in the same way as an attribute null.

 if(obj.length == null){
  ...código
 }

Or using the method: hasOwnProperty('Attribute'), where returns a boolean stating whether this property is null or not

obj = new Object(); 
obj.propUm = null;
obj.hasOwnProperty('propUm'); // retorna true
obj.propDois = undefined;
obj.hasOwnProperty('propDois'); // retorna true

If you really want to instantiate a null object, you should do it as follows:

obj = null

Because by creating obj = {}, you are instantiating an object (therefore no longer null)