How to remove null from array in JavaScript

Question

I want to delete null elements in my array

 [ [ null, [ [Array], [Array] ] ] ]

The desired structure is [ [[Array],[Array]], [[Array],[Array]], [[Array],[Array]] ]

if any of the objects are undefined/null such as :

[ [[Array],[]],  [[Array],[Array]],  [[Array],[Array]] ]

I wish to remove the full element [[Array],[]]

The 'yes' and 'no' are correctly identifying which elements have the undefined. So I know this code is functioning properly. I tried assigning the empty array as null and then filtering by adding to new array if != null but it did not work.

var filter = Total[0][i];

filter.forEach(e => {
    if ((e[0] !== undefined)&&(e[1] !== undefined)) {
        console.log('yes');
    } else {
        console.log('no');
        Total[0][i] = null;
    }
});

var totalArray = [];

const resultFilter = Total.filter(arr => arr != null);

var Filtereddata = resultFilter.filter(function(element) {
    return element !== null;
}

I am unsure how to remove the element or filter into a new array without null. The null Array is causing problems client side with extra , it would be better to remove the index/element altogether.

Please update the question with code creating example input, and with examples of the output you want. — T.J. Crowder
– T.J. Crowder, Commented Apr 10, 2019 at 16:55

Jonas Wilms · Accepted Answer · 2019-04-10 16:56:32Z

2

You could just recursively filter out nulls:

 const noNull = array => array
    .map(el => Array.isArray(el) ? noNull(el) : el)
    .filter(it => it !== null);

If you also want to remove empty arrays, you can replace [] with null:

 const noEmpty = array => array.length ? array : null;

Then change the recursive call from noNull(el) to noEmpty(noNull(el))

answered Apr 10, 2019 at 16:56

Jonas Wilms

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2 Comments

annaM Over a year ago

Fabulous, thank you very much! this worked for me! :)

Jonas Wilms Over a year ago

@annaM glad to help :)

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