How to verify Array of objects is empty/null/undefined in js

Question

I have a js array of objects as follows:

var person = [{
  firstName: "",
  lastName: "Doe",
  age: 46
}, {
  firstName: "John",
  lastName: "",
  age: 35
}];

How do i find out if at least of the objects in the array, for eg firstName: or lastName: is empty or not? The result of the called function needs only to be true or false.

npm install joi if it is in node. for browsers there are also plenty of validators of all kinds — Daniel Khoroshko
– Daniel Khoroshko, Commented Dec 31, 2017 at 5:44

palaѕн · Accepted Answer · 2017-12-31 05:42:30Z

1

You can use filter & length like:

const isEmpty = person.filter(x => !x.firstName || !x.lastName).length > 0

Or, using some like:

const isEmpty = person.some(x => !x.firstName || !x.lastName);

^EDIT:-

function filterItems(TableData) {
  return TableData.filter(function(el) {
    return Object.values(el).some(v => !v);
  })
}

edited Dec 31, 2017 at 5:42

answered Dec 31, 2017 at 5:06

palaѕн

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7 Comments

Andrew Li Over a year ago

Use Array#some instead to get rid of the length check

Raky Over a year ago

Thanks for prompt response. But in case we need to generalize the code with n number of objects in each array element then?

Andrew Li Over a year ago

@palaѕн OP means an arbitrary amount of object values. So person.some(x => Object.values(x).some(val => !val))

Raky Over a year ago

I am trying something like this

function filterItems(TableData) { 	  return TableData.filter(function(el) { 		   		  return isEmpty(el); 	  }) 	} 	 	function isEmpty(item) { 		if(item.length > 0){    			return false;//this element is NOT empty 		}else{ 		   return true;//this element is empty 		} 	}

Raky Over a year ago

yes sir, works truly smooth. This is of course a generalized function applicable to any array of objects. Thank you.

|

brk · Accepted Answer · 2017-12-31 05:10:22Z

1

You can use forEach to iterate over the array and use Object.values to get all the value. Then use indexOf to test if the value matches.Use a variable to save the state

var person = [{
    firstName: "",
    lastName: "Doe",
    age: 46
  },
  {
    firstName: "John",
    lastName: "",
    age: 35
  }
];

function testArray(arr) {
  var isEmpty = false
  arr.forEach(function(item) {
    if (Object.values(item).indexOf("") !== -1) {
      isEmpty = true
    }

  })
  return isEmpty;
}
console.log(testArray(person))

answered Dec 31, 2017 at 5:10

brk

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Comments

jmowla · Accepted Answer · 2017-12-31 05:49:51Z

1

If at least one item is null or empty, it returns false

const person = [{
  firstName: "",
  lastName: "Doe",
  age: 46
}, {
  firstName: "John",
  lastName: "",
  age: 35
}];

const allItemsHaveValue = person.map(o => Object.values(o).every(v => v)).every(v => v);

console.log('All items have value: ', allItemsHaveValue);

answered Dec 31, 2017 at 5:49

jmowla

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