How to check if string array only contains empty strings

Question

I am currently looking for a solution how to check a string array with only empty strings. Is there an efficient way to achive this behavior?

['', '', '', ''] // This should be true
['', null, null, ''] // This should be true
['a', '', '', ''] // This should be false

Maybe I just expressed myself a bit unfortunate. I just really wanted to have a clean solution without, maybe something that exists in javascript already without reimplementing it or adding an additional loop for the sake of clean code. — Ling Vu
– Ling Vu, Commented Nov 19, 2019 at 8:03
if you mean a user defined loop (eg for loop or loops made by using some,every,forEach, etc) you could do a join('') (internal loop) and check for empty string — Patrick Evans
– Patrick Evans, Commented Nov 19, 2019 at 8:05

Nimer Awad · Accepted Answer · 2019-11-19 08:10:06Z

6

You can use some function:

let arr = ['', '', '', ''];
arr.some(Boolean);

it will check if some elements not false value ('', 0, null, undefined, false), if all of them are false; it will return true.

edited Nov 19, 2019 at 8:10

answered Nov 19, 2019 at 8:03

Nimer Awad

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Nina Scholz · Accepted Answer · 2019-11-19 08:01:23Z

5

You need a loop, preferably with a short circuit.

const check = array => !array.some(Boolean);

console.log(check(['', '', '', '']));     //  true
console.log(check(['', null, null, ''])); //  true
console.log(check(['a', '', '', '']));    // false

answered Nov 19, 2019 at 8:01

Nina Scholz

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Ling Vu · Accepted Answer · 2019-11-19 08:12:45Z

0

Thanks to all of you incl. Patrick Evans. I use the join('') method. This looks fairly clean to me.

let arr = ['', '', '', ''] // This should be true

console.log(Boolean(arr.join(''));

answered Nov 19, 2019 at 8:12

Ling Vu

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1 Comment

Nimer Awad Over a year ago

Join method will loop through all items; no matter what the element is, but some will break the loop and return value on first true element.

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