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.

I think the description is more suited to describe observable arrays. — Faisal Rahman Avash
– Faisal Rahman Avash, Commented May 27, 2019 at 4:38

Vivekanand Panda · Accepted Answer · 2019-05-27 06:22:09Z

12

Use every():

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

edited May 27, 2019 at 6:22

Vivekanand Panda

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answered May 27, 2019 at 4:34

Jack Bashford

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2 Comments

Terry Over a year ago

Just out of curiousity: is it better to use == or === for this case, or does it not really matter at all?

Jack Bashford Over a year ago

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)

Srinivasan Sekar · Accepted Answer · 2019-05-27 05:02:27Z

11

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, ""]

edited May 27, 2019 at 5:02

answered May 27, 2019 at 4:34

Srinivasan Sekar

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8 Comments

Eddie Over a year ago

You can also trim() if there are spaces in the array :)

Vikash_Singh Over a year ago

array.join("").replace(/\s/gi,'').length==0 will be improved version of this answer.

Atal Shrivastava Over a year ago

I dont want to trim because that blank values i have to use

Srinivasan Sekar Over a year ago

I hope he wasn't worried about spaces , updated the answer anyway. @VikashSingh

Shidersz Over a year ago

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.

|

MMMahdy-PAPION · Accepted Answer · 2022-01-17 00:22:58Z

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:

.some(Boolean) ~40M ops/s (Operation per second)
isArrayEmpty() ~36M ops/s (~10% slower)
.filter(Boolean).length ~9M ops/s (~75% slower)
.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.

Easily the best answer here. This should be the accepted answer.

Shidersz · Accepted Answer · 2019-05-27 05:26:45Z

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;}

answered May 27, 2019 at 5:26

Shidersz

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Comments

Akrion · Accepted Answer · 2019-05-27 06:51:50Z

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>

Naor Tedgi · Accepted Answer · 2019-05-27 04:36:19Z

1

const isEmpty=arr=>{
  return arr.filter(it=>it.length>0).length ==0
}

arr1 = ["",""]
arr2 = ["1",""]

console.log(isEmpty(arr1))
console.log(isEmpty(arr2))

answered May 27, 2019 at 4:36

Naor Tedgi

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Comments

yaswanth · Accepted Answer · 2019-05-27 05:01:34Z

1

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));

answered May 27, 2019 at 5:01

yaswanth

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Comments

Vivekanand Panda · Accepted Answer · 2019-05-27 06:17:11Z

1

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

answered May 27, 2019 at 6:17

Vivekanand Panda

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Comments

Badri Chorapalli · Accepted Answer · 2019-05-27 06:25:31Z

1

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))

answered May 27, 2019 at 6:25

Badri Chorapalli

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Comments

sagar saini · Accepted Answer · 2019-06-29 02:33:40Z

1

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");
}
}

edited Jun 29, 2019 at 2:33

answered May 31, 2019 at 6:44

sagar saini

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