Determining if all attributes on a javascript object are null or an empty string

Question

What is the most elegant way to determine if all attributes in a javascript object are either null or the empty string? It should work for an arbitrary number of attributes

Answer 1

Just complementing the past answers: they'll work if your object doesn't contain arrays or objects. If it does, you'll need to do a 'deep check'.

So I came up with this solution. It'll evaluate the object as empty if all its values (and values inside values) are undefined, {} or [].

function deepCheckEmptyObject(obj) {
    return Object.values(obj).every( value => {
        if (value === undefined) return true;
        else if ((value instanceof Array || value instanceof Object) && _.isEmpty(value) ) return true;
        else if (value instanceof Array && !_.isEmpty(value)) return deepCheckEmptyArray(value);
        else if (value instanceof Object && !_.isEmpty(value)) return deepCheckEmptyObject(value);
        else return false;
    });
}

function deepCheckEmptyArray(array) {
    return array.every( value => {
        if (value === undefined) return true;
        else if ((value instanceof Array || value instanceof Object) && _.isEmpty(value)) return true;
        else if (value instanceof Array && !_.isEmpty(value)) return deepCheckEmptyArray(value);
        else if (value instanceof Object && !_.isEmpty(value)) return deepCheckEmptyObject(value);
        else return false;
    });
}

Note it uses Lodash's .isEmpty() to do the heavy work after we 'isolated' a value. Here, Lodash is imported as '_'.

Hope it helps!

Answer 2

Building on top of other answers I would use lodash to check isEmpty on the object, as well as its properties.

const isEmpty = (object) => return _.isEmpty(object) || !Object.values(object).some(x => !_.isEmpty(x))

Answer 3

This skip the function attribute

function checkIsNull(obj){
		let isNull=true;
		for(let key in obj){
			if (obj[key] && typeof obj[key] !== 'function') {
				isNull = false;
			}
		}
		return isNull;
	}

var objectWithFunctionEmpty={
  "name":undefined,
  "surname":null,
  "fun": function (){ alert('ciao'); }
}

var objectWithFunctionFull={
  "name":undefined,
  "surname":"bla bla",
  "fun": function (){ alert('ciao'); }
}

checkIsNull(objectWithFunctionEmpty); //true
checkIsNull(objectWithFunctionFull); //false

Answer 4

Here's my version, specifically checking for null and empty strings (would be easier to just check for falsy)

function isEmptyObject(o) {
    return Object.keys(o).every(function(x) {
        return o[x]===''||o[x]===null;  // or just "return o[x];" for falsy values
    });
}

Answer 5

Edit: As user @abd995 noted in the comments, using Array.some() is more efficiënt as it stops the loop when the condition is met:

const isEmpty = !Object.values(object).some(x => (x !== null && x !== ''));

Original: 2017 answer: Check all values with Object.values(). Returns an array with the values which you can check with Array.every() or Array.some()... etc.

const isEmpty = Object.values(object).every(x => (x === null || x === ''));

• MDN Object.values()
• MDN Array.every()

Answer 6

Based on tymeJv's answer =)

function checkProperties(obj) {
var state = true;
  for (var key in obj) {
    if ( !( obj[key] === null || obj[key] === "" ) ) {
        state = false;
        break;
    }
  }
  return state;
}

var obj = {
  x: null,
  y: "",
  z: 1
}

checkProperties(obj) //returns false

Hope it helps =)