Checking for empty values in an array using Javascript

My array looks like this:

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

I am trying to create an alert for when all the values in the array are blank, meaning the array should be like this:

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

Any suggestions on how I can make this work?

javascriptarrays

Answer №1

Utilize the every() method:

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

Answer №2

Give this a shot:

When all elements are empty strings, the length is zero.

If you need to eliminate spaces:

After removing all spaces, if the length is still zero.

Keep in mind:

This method will not be effective for arrays containing various data types like 

["", [], "", null, undefined, ""]

Answer №3

TL;DR (Quick & Easy)
[].some(Boolean)  //  Empty : false   |   Not Empty : true
Explanation

This approach combines native functions like Boolean with .some() or .filter(), or .join() to achieve the desired outcome:

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

In addition, you can create a custom 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

Considerations about performance:

  1. .some(Boolean) ~40M ops/s (Operations 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 result in even lower performance, approximately 5% slower in these cases.

Note (2): This method works effectively when all array items are assured to be strings. For other falsy values (null or false, etc.), option #3 (using join) may not yield the correct result.

Answer №4

If you're looking for a simple solution, consider using a traditional for loop:

function checkBlanks(arr)
{
    for (var i = 0; i < arr.length; i++)
    {
        if (arr[i] !== "") return false;
    }

    return true;
}

console.log(checkBlanks(["", "", "", "1", "", ""]));
console.log(checkBlanks(["", "", "", "", "", ""]));
console.log(checkBlanks(["", [], "", null, undefined, ""]));
.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

Answer №5

If you're looking for a more general method to compact arrays by removing falsey values and then check the length, here's one approach:

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

If this specific use case is all you're concerned with, you can also utilize 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", "", "", ""]))

Another option is using Array.reduce:

let isEmpty = a => !a.reduce((r,c) => `${r}${c}`).length

console.log(isEmpty(["", "", "", "", "", ""]))
console.log(isEmpty(["", "", "1", "", "", ""]))

Consider also utilizing Array.filter:

let isEmpty = a => !a.filter(x => x.toString().length).length

console.log(isEmpty(["", "", "", "", "", ""]))
console.log(isEmpty(["", "", "1", "", "", ""]))

It's important to note that these methods are specifically tailored to your current input array, not accounting for arrays containing objects or other complex elements.

If you have access to lodash, you can achieve this with _.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>

You can also use _.compact from lodash which 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

function checkEmptyArray(array) {
  return array.filter(item => item.length > 0).length == 0;
}

let emptyArr = ["", ""];
let nonEmptyArr = ["1", ""];

console.log(checkEmptyArray(emptyArr));
console.log(checkEmptyArray(nonEmptyArr));

Answer №7

const array1 = ["", "", "", "1", "", ""];
const array2 = ["", "", "", "", "", ""];

function checkEmptyValues(arr) {
  let count = 0;
  for(let j = 0; j < arr.length; j++) {
    if(arr[j].trim().length === 0) {
      count++;
    }
  }
  return count === arr.length
}

console.log(checkEmptyValues(array2));
console.log(checkEmptyValues(array1));

Answer №8

function checkEmpty (arr){
  return arr.every(item => item === "")
};
let firstArr = ["", "", "", "1", "", ""];
let secondArr = ["", "", "", "", "", ""] 
console.log(checkEmpty(firstArr));
console.log(checkEmpty(secondArr));

Answer №9

I created a simple function to check for empty arrays that is compatible with all web 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) Keep the array size constant
2) Count the number of empty values in the array and save it as a variable (EmptyValues)
3) If (EmptyValue == length) { Alert with your desired message}

function checkBlankvalues(arr){
var emptyValues=0,length=arr.length;
// Loop to find empty values in the array
for(var i=0;i<arr.length;i++)
{ 
   if(arr[i]="")
   {
     emptyValues++;
   }
}
if(length==emptyValue)
{
 //alert("array is blank");
}
}

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