How to check if all array values are blank in Javascript

Question

I have an array like:

["", "", "", "1", "", ""]

I want to alert when all the array values are blanks, i.e, when the array is like this:

["", "", "", "", "", ""]

How can I achieve this.

• Faisal Rahman Avash: Possible duplicate of How to watch for array changes?
• Jack Bashford: How is it a duplicate @Faisal?
• Faisal Rahman Avash: I think the description is more suited to describe observable arrays.
• Jaydeep Mor: But it is not be duplicate @Faizal.
• Jack Bashford: Erm...the above doesn't need to observe anything @Faisal

Answer 1

Use every():

const allEmpty = arr => arr.every(e => e === "");
console.log(allEmpty(["", "", "", "1", "", ""]));
console.log(allEmpty(["", "", "", "", "", ""]));

• Terry: Just out of curiousity: is it better to use == or === for this case, or does it not really matter at all?
• Jack Bashford: Whoops - I missed that @Terry. Thanks! It's better to use === because if an array element is 0, then it'll be removed (because 0 == ""). Try it - it evaluates to true! (Weird, I know - but they both evaluate to false)

Answer 2

Try this,

["", "", "", "", "", ""].join("").length==0

If you want to remove spaces,

["", "", "", "", "", ""].join("").replace(/\s/gi,'').length==0

Note :

This will not work for inputs like ["", [], "", null, undefined, ""]

• Eddie: You can also trim() if there are spaces in the array :)
• Vikash_Singh: array.join("").replace(/\s/gi,'').length==0 will be improved version of this answer.
• Atal Shrivastava: I dont want to trim because that blank values i have to use
• Srinivasan Sekar: I hope he wasn't worried about spaces , updated the answer anyway. @VikashSingh
• Shidersz: Note this will returns true for an input like: ["", [], "", null, undefined, ""]. If you are strictly looking that all items are empty strings "" then this won't be good.

Answer 3

TL;DR (Fastest & Simple)

[].some(Boolean) // Empty : false | Not Empty : true

Explanation

Mixture of native functions, Boolean with .some() or .filter() or using .join() can return the expected result:

var a=['','','','',''], // Empty
 b=['','','x','','']; // Not Empty
// Is Not Empty?
// #1
console.log( a.some(Boolean) ); // false
console.log( b.some(Boolean) ); // true
// #2
console.log( a.filter(Boolean).length ); // = 0
console.log( b.filter(Boolean).length ); // != 0
// #3
console.log( a.join('')!='' ); // false
console.log( b.join('')!='' ); // true

Also a user-defined function:

var a=['','','','',''], // Empty
 b=['','','x','','']; // Not Empty
 
function isArrayEmpty(a) { 
 for (var i = 0; i < a.length; i++) 
 if (a[i]) return false;
 return true;
}
console.log( isArrayEmpty(a) ); // true
console.log( isArrayEmpty(b) ); // false

But about performance:

1. .some(Boolean) ~40M ops/s (Operation per second)
2. isArrayEmpty() ~36M ops/s (~10% slower)
3. .filter(Boolean).length ~9M ops/s (~75% slower)
4. .join('')!='' ~4M ops/s (~90% slower)

Note (1): Using Arrow functions (a)=>a instead of Boolean, will make the performances even lower, in these cases about ~5% slower.

Note (2): The expected result is same just when we are sure that all of array items are String. About other falsy s (null or false ...) items, the option #3 (join) will not work.

• Michael M.: Easily the best answer here. This should be the accepted answer.

Answer 4

You can always use a basic for loop as a solution for your problem:

function allBlanks(arr)
{
 for (var i = 0; i < arr.length; i++)
 {
 if (arr[i] !== "") return false;
 }
 return true;
}
console.log(allBlanks(["", "", "", "1", "", ""]));
console.log(allBlanks(["", "", "", "", "", ""]));
console.log(allBlanks(["", [], "", null, undefined, ""]));

.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

Answer 5

Here is also a more generic approach which would compact the array removing all falsey values and then check the remaining length:

let compact = a => a.reduce((r,c) => (!!c ? r.push(c) : null, r),[])
let isEmpty = array => compact(array).length == 0
console.log(isEmpty(["", false, 0, "", null, undefined])) // true
console.log(isEmpty(["", 1])) // false
console.log(isEmpty(["", []])) // false
console.log(isEmpty(["", {}])) // false

But if this is the only use case you care about then you can also use Array.some:

let isEmpty = a => !a.some(x => x !== '')
// OR let isEmpty = a => !a.some(x => x.toString().length > 0)
console.log(isEmpty(["", "", "", "", "", ""]))
console.log(isEmpty(["", "", "1", "", "", ""]))

You could also use Array.reduce:

let isEmpty = a => !a.reduce((r,c) => `${r}${c}`).length
console.log(isEmpty(["", "", "", "", "", ""]))
console.log(isEmpty(["", "", "1", "", "", ""]))

Array.filter:

let isEmpty = a => !a.filter(x => x.toString().length).length
console.log(isEmpty(["", "", "", "", "", ""]))
console.log(isEmpty(["", "", "1", "", "", ""]))

This will only be valid check against your current input however. Not against cases with arrays, object literals etc as part of your input array.

---

If you are using lodash this could be (via _.every and _.isEmpty):

let isArrayEmpty = a => _.every(a, _.isEmpty)
console.log(isArrayEmpty(["", "", "", "", "", ""]))
console.log(isArrayEmpty(["", "", "1", "", "", ""]))

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

or also via _.compact which also removes falsey values:

let isArrayEmpty = a => !_.compact(a).length
console.log(isArrayEmpty(["", "", "", "", "", ""]))
console.log(isArrayEmpty(["", "", "1", "", "", ""]))

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Answer 6

const isEmpty=arr=>{
 return arr.filter(it=>it.length>0).length ==0
}
arr1 = ["",""]
arr2 = ["1",""]
console.log(isEmpty(arr1))
console.log(isEmpty(arr2))

Answer 7

var arr1 = ["", "", "", "1", "", ""];
var arr2 = ["", "", "", "", "", ""];
function checkArrValEmpty(arr) {
 let count = 0;
 for(let i = 0; i < arr.length; i++) {
 if(arr[i].trim().length === 0) {`enter code here`
 count++;
 }
 }
 return count === arr.length
}
console.log(checkArrValEmpty(arr2));
console.log(checkArrValEmpty(arr1));

Answer 8

function isEmpty (arr){
 return arr.every(e => e === "")
};
let a = ["", "", "", "1", "", ""];
let b = ["", "", "", "", "", ""] 
console.log(isEmpty(a));
console.log(isEmpty(b));

Answer 9

I implemented small function for checking empty array which will work in all browsers.

var list=["1", [], "", null, undefined, ""];
var listE=["", "", "","", "", "", ""];
var listE1=["", [], "", null, undefined, ""];
function isArrayEmpty(arr){
return arr.toString().replace(/,/g, '')=="";
}
alert(isArrayEmpty(list))
alert(isArrayEmpty(listE))
alert(isArrayEmpty(listE1))

Answer 10

1) Maintain the size of array as length
2) Find the no. of empty values in the array and store it in say an variable (EmptyValues)
3) Check if (EmptyValue== length) { Give Alert whatever you want}

function checkBlankvalues(arr){
var emptyValues=0,length=arr.length;
//for finding empty vales in array till now
for(var i=0;i<arr.length;i++)
{ 
 if(arr[i]="")
 {
 emptyValues++;
 }
}
if(length==emptyValue)
{
 //alert("array is blank");
}
}