Remove Nullish values from multidimensional array?

Question

I have an array res with some nullish values, and I have a function remove that is supposed return an array with nulls and undefined removed, but I can't get it to work on my array. I've seen plenty of answers on this sort of thing, in fact my remove function originated from one of them, but I can't seem to get it to work.

res =    
[
{
    "1yKKftO0iOyvsacrW1mEr-FylurU8-fwaefewafw": [
        "[email protected]",
        "[email protected]",
        null,
        "[email protected]"
    ]
},
{
    "149Lmt-gweagewfrthjregjiojoinONEDOnonao": [
        "[email protected]"
    ]
},
{
    "JG043AHF0GJA0EWJIFJO00WIJF-UffFWEAk8QRg4": [
        "[email protected]",
        "[email protected]"
    ]
},
{
    "1u-Frw5I4agI-FWKE0AFJ0WEJG0JEFDALKFEWA-ns": [
        null,
        "[email protected]"
    ]
},
{
    "FAWGETAIODIOFAIJDSOIFJWEOFijewaofifejowef": [
        "[email protected]"
    ]
},
{
    "fwaejf0JF0EWJIJFFJMojfeoijfewJEJFI0i0fje": [
        "[email protected]"
    ]
},
{
    "FJ09Ejf093ejfie0jfeiJFEJF0IWJFEIJFOEJWow": [
        "[email protected]"
    ]
}
]

var remove = function (array) {
var result = [];

array.forEach(function (item) {
  if (Array.isArray(item) && item.length!=0) {
    // Item is a nested array, go one level deeper recursively
    result.push(remove(item));
  }
  else if (typeof item !== null) {
    result.push(item);
  }
});

return result;
};

console.log(remove(res));

What's the desired output? The same as the input structure, but without the nulls? — CertainPerformance
– CertainPerformance, Commented Mar 5, 2022 at 18:01

cmgchess · Accepted Answer · 2022-03-05 18:37:08Z

Here is a solution without recursion that will work for the nesting level given in example. Also will work if a single array element has multiple key value pairs.

let res =[{"1yKKftO0iOyvsacrW1mEr-FylurU8-fwaefewafw": ["[email protected]","[email protected]",null,"[email protected]"]},{"149Lmt-gweagewfrthjregjiojoinONEDOnonao": ["[email protected]"]},{"JG043AHF0GJA0EWJIFJO00WIJF-UffFWEAk8QRg4": ["[email protected]","[email protected]"]},{"1u-Frw5I4agI-FWKE0AFJ0WEJG0JEFDALKFEWA-ns": [undefined,"[email protected]"]},{"FAWGETAIODIOFAIJDSOIFJWEOFijewaofifejowef": ["[email protected]"]},{"fwaejf0JF0EWJIJFFJMojfeoijfewJEJFI0i0fje": ["[email protected]"]},{"FJ09Ejf093ejfie0jfeiJFEJF0IWJFEIJFOEJWow": ["[email protected]",null]}]

var remove = function (array) {

return array.map(function (item) {
  let x = Object.entries(item).map((y) => {
    return [y[0],y[1].filter((z)=> z!==undefined && z!==null)]
  })
  return Object.fromEntries(x)
});
};

console.log(remove(res));

Zorby · Accepted Answer · 2022-03-05 18:12:57Z

1

If you want to remove nulls as well as undefineds, you probably want to replace else if (typeof item !== null) with else if (typeof item != null)

answered Mar 5, 2022 at 18:12

Zorby

113 bronze badges

Comments

Nikhil Devadiga · Accepted Answer · 2022-03-05 19:10:56Z

What's happening

The elements of res are Objects. Notice that in the nested function call of remove

result.push(remove(item));

the item being passed are elements of res thus not an array. So when remove(item) is called the check Array.isArray(item) fails and nothing is sorted out. To get the inner array make add this line.

var values = Object.values(item)

Now handle the cases of item being null, Object and Array.

Solution

Here's my Attempt at the solution. (I hope you don't mind ES6) This does work on this particular (not sure about other cases)

const remove = (item) => {
  if (item) {
    console.log('not null', item)
    if (Array.isArray(item)) {
      const result = []
      for (let elem of item) {
        const cleanedElem = remove(elem)
        // Maybe use Nullish coalescing operator ?
        if (cleanedElem !== null && cleanedElem !== undefined)
          result.push(cleanedElem)
      }
      return result
    } else if (typeof item === 'string' || typeof item === 'number') {
      return item
    } else if (item) {
      const result = {}
      for (let pair of Object.entries(item)) {
        const [key, value] = pair
        const cleanedValue = remove(value)
        // Maybe use Nullish coalescing operator ?
        if (cleanedValue !== null && cleanedValue !== undefined)
          result[key] = remove(cleanedValue)
      }
      return result
    }
  }
}

cleansed = remove(res)
console.log(cleansed);

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